Share LaTeX Equations as Links

Build a static LaTeX renderer that saves and shares documents in URL fragments.

Introduction

30 Second Summary

A neatly formatted equation is easy to show on your screen. Sharing the exact result often means sending source text that the other person must render themselves.

In this project, you will build a one-page tool that turns a LaTeX document into a shareable link. You will publish the finished tool with GitHub Pages.

What You'll Build

Picture a copied link opening in a fresh browser tab with your formatted maths ready to share.

By the end of this project, you'll have:

A live equation editor that renders formatted maths while the URL fragment stores your document.
A Copy link button that produces a bookmarkable URL which reopens the same document in a fresh tab.
A compressed mode with on-screen link lengths that shows how much shorter a long document becomes.
Secret Mission: An optional challenge to push your link-sharing skills further.

Are there any prerequisites?

You'll need a browser plus a text editor. You'll also need a GitHub account for publishing the page.

Everything runs with free static hosting. This project has no expected cost.

Before We Start

A shareable equation link needs a browser that can display it. A code editor gives you a place to write the HTML behind it.

Git tracks your page on your computer. GitHub publishes it when the build is ready.

In this step, get ready to:

Prepare your local web workspace.
Verify that Git is available.
Access your GitHub account.

Check your browser and code editor

Your browser is already proving itself by showing this lesson. Your code editor needs one quick check before you start writing the page.

Press Cmd+Space on macOS or the Windows key on Windows to open system search.
Type the name of your code editor into the search field.
Press Enter to open the editor.

✔️ My editor opens

Your editor is ready when you can see an empty editing window. That gives you a workspace for the page you build next.

ⓧ I need a code editor

Choose an installable code editor that supports HTML files.
Download its installer from the editor's official website.

You should now see the installer in your downloads folder.

Install the editor using its recommended settings.
Repeat the system search to open the editor.

You should see an empty editing window when the installation is complete.

Editor Still Not Opening?

Confirm that you downloaded the installer for your operating system. Help me troubleshoot my code editor installation.

Verify your Git installation

Git records each version of the page as the project grows. A version check confirms that its command-line tool is ready.

Press Cmd+Space on macOS or the Windows key on Windows to open system search.
Type Terminal on macOS or PowerShell on Windows.
Press Enter to open the command-line app.
Predict whether Git will print a version or report that the command is unavailable.
Check your Git installation by running this command:

git --version

What Does This Command Do?

The git --version command asks Git to print the installed version. A version in the output confirms that your command line can find Git.

✔️ I see a Git version

Your output begins with git version followed by a version number. Git is ready to track the project.

ⓧ The command is unavailable

Open the official Git installation guide.
Choose your operating system to reveal its installation options.

You should see installation methods matched to your computer.

Complete the recommended installation method for your operating system.
Return to your command-line app after the installation finishes.
Verify the installation by running this command:

git --version

What Does This Check Confirm?

The git --version command now checks whether the completed installation is available from your command line. Successful output begins with git version.

You should now see a Git version number in the output.

Git Still Unavailable?

Close your command-line app after installing Git. Reopen it before checking again so it can detect the new installation.

If the command is still unavailable, help me troubleshoot my Git installation.

Access your GitHub account

GitHub hosts the repository that publishes your finished page. You need a personal account with a verified email address before you can create that repository.

GitHub handles your credentials on its own sign-in page. This project never asks you to paste those credentials into code.

✔️ I already have a GitHub account

Open GitHub in your browser.
Select Sign in.
Authenticate with your existing account.

You should reach your signed-in GitHub home page.

ⓧ I need a GitHub account

Open the GitHub account creation page.

You should see GitHub's account creation flow in your browser.

Follow the prompts to create your personal account.
Verify the email address connected to the account.

Having Trouble Creating the Account?

Use an email address that is available for a personal GitHub account. Help me troubleshoot my GitHub account setup.

Predict whether GitHub will show your signed-in home page.
Return to the GitHub home page to check your account access.

You should see your signed-in GitHub home page instead of account access prompts.

That is your setup complete. Every tool for the first build is ready.

Your workspace is ready. Next up, you will create index.html and render your first equation in the browser.

Render a Hard-Coded Equation

A link-based equation tool needs proof that the browser can typeset its source. Browsers display LaTeX source as characters until a renderer converts it.

In this step, you'll create a static HTML page that loads KaTeX from a CDN. You'll render one fixed equation as formatted maths.

In this step, get ready to:

Create a local project folder on your Desktop.
Load the KaTeX styles and browser library in index.html.
Render a hard-coded equation in your browser.

Create the local project files

Your project starts as one local folder containing one HTML file. Keeping this first version small gives you a quick path to a visible result.

Press Cmd+Space on macOS or the Windows key on Windows to open your search bar.
Type the name of your code editor into the search bar.

You'll see your code editor in the search results.

Press Enter to open your code editor.

You'll see your code editor ready for a folder.

Use your code editor's folder controls to create a folder named latex-link on your Desktop.

You'll see latex-link in the editor's file sidebar. This confirms that every project file lands in the same place.

Use the file controls in the sidebar to create index.html inside latex-link.

You'll see index.html listed inside the folder.

Render the equation with KaTeX

KaTeX needs a stylesheet for its mathematical fonts. Its browser library provides the katex.render() function that writes formatted maths into a page element.

Why use a CDN?

A CDN serves the KaTeX files directly to your browser. This keeps your project to a single HTML file.

A local package would add a build process. The CDN gives this static page everything it needs when the page opens.

Build the first version of index.html by replacing its contents with the code below:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>LaTeX Link Renderer</title>
  <!-- Load KaTeX styles so rendered equations use mathematical fonts. -->
  <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.19.0/dist/katex.min.css" integrity="sha384-3rdsX6e5mueWyoweR9NIVmtEsUkokpBT/0ALqKKIBMr9j4qhHkaIkAcGgsE6uVlp" crossorigin="anonymous">
  <!-- Load the KaTeX browser API before the page finishes loading. -->
  <script defer src="https://cdn.jsdelivr.net/npm/katex@0.19.0/dist/katex.min.js" integrity="sha384-QFFtAGzvvj+bfgCGxXJlNZZR1nXEZgvG8tDLCCY1F19xl20WlfTYgguB4VcNdxYk" crossorigin="anonymous"></script>
</head>
<body>
  <main>
    <h1>LaTeX Equation</h1>
    <!-- KaTeX writes the formatted equation into this element. -->
    <div id="equation-output"></div>
  </main>
  <script>
    // Wait until the deferred KaTeX script and page elements are ready.
    document.addEventListener("DOMContentLoaded", () => {
      // Keep a reference to the element that receives the formatted equation.
      const equationOutput = document.getElementById("equation-output")
      // Render one fixed LaTeX expression as a display equation.
      katex.render("c = \\pm\\sqrt{a^2 + b^2}", equationOutput, {
        displayMode: true
      })
    })
  </script>
</body>
</html>

What does this code do?

The stylesheet gives the rendered equation its mathematical fonts and spacing.
The deferred script loads the KaTeX 0.19.0 browser API from the CDN.
The equation-output element provides a destination for the formatted equation.
The DOMContentLoaded listener delays rendering until the page is ready.
The displayMode option presents the expression as a standalone equation.

Save index.html.

Before you open the page, do you expect to see the LaTeX source or a typeset equation?

Reveal index.html in Finder on macOS or File Explorer on Windows.
Double-click index.html to open it in your browser.

You'll see the equation c = ±√(a² + b²) as formatted maths below the page heading. That's your first visible win: the browser is rendering LaTeX through KaTeX.

Equation missing?

Check that your computer has an internet connection so the CDN files can load.
Compare both KaTeX URLs in your file with the code above.
Check that equation-output has the same spelling in the HTML element and the JavaScript lookup.

If the page remains blank, help me debug why my KaTeX equation is not rendering.

✔️ Awesome, I've got everything!

Your saved index.html now contains the complete first version of the equation renderer.

ⓧ I'd like to double check the full code

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>LaTeX Link Renderer</title>
  <!-- Load KaTeX styles so rendered equations use mathematical fonts. -->
  <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.19.0/dist/katex.min.css" integrity="sha384-3rdsX6e5mueWyoweR9NIVmtEsUkokpBT/0ALqKKIBMr9j4qhHkaIkAcGgsE6uVlp" crossorigin="anonymous">
  <!-- Load the KaTeX browser API before the page finishes loading. -->
  <script defer src="https://cdn.jsdelivr.net/npm/katex@0.19.0/dist/katex.min.js" integrity="sha384-QFFtAGzvvj+bfgCGxXJlNZZR1nXEZgvG8tDLCCY1F19xl20WlfTYgguB4VcNdxYk" crossorigin="anonymous"></script>
</head>
<body>
  <main>
    <h1>LaTeX Equation</h1>
    <!-- KaTeX writes the formatted equation into this element. -->
    <div id="equation-output"></div>
  </main>
  <script>
    // Wait until the deferred KaTeX script and page elements are ready.
    document.addEventListener("DOMContentLoaded", () => {
      // Keep a reference to the element that receives the formatted equation.
      const equationOutput = document.getElementById("equation-output")
      // Render one fixed LaTeX expression as a display equation.
      katex.render("c = \\pm\\sqrt{a^2 + b^2}", equationOutput, {
        displayMode: true
      })
    })
  </script>
</body>
</html>

Your local page can now turn a LaTeX string into formatted maths. Next, you'll let the link itself supply the equation source.

Render LaTeX from the URL

Your page can already render one hard-coded equation. A shareable tool needs each URL to carry its own LaTeX source.

In this step, you will turn the URL fragment into the document source. KaTeX will render the decoded value.

In this step, get ready to:

Replace the hard-coded source with the decoded URL fragment.
Reload the page with a different fragment to render a new equation.

Decode LaTeX from the URL fragment

The fragment starts after the # character. URL encoding keeps special characters intact while the equation travels inside an address.

Click the address bar in the browser from earlier.
Append #x%5E2 to the current page URL.
Press Enter.

Your address now carries the encoded equation source after #.

In index.html, locate the existing katex.render call.
Select the hard-coded LaTeX value used as the first argument.
Make the fragment the render source by replacing the selected first argument with this expression:

decodeURIComponent(location.hash.slice(1))

How Does the Fragment Become LaTeX?

The location.hash property reads the fragment with its leading # character.
The .slice(1) method removes that leading marker.
The decodeURIComponent(...) function restores percent-encoded characters before KaTeX receives the source.

Save index.html.

Before you reload, do you expect the old hard-coded value or the URL fragment to control the equation? The next refresh tests your prediction.

Reload the page by pressing Cmd+R on macOS or Ctrl+R on Windows.

You will see x with a superscript 2. The fragment now controls the equation that KaTeX renders.

Still Seeing the Hard-Coded Equation?

Confirm the expression replaced only the first argument in katex.render.
Confirm the existing equation output element remains the second argument.
Check that the browser URL ends with #x%5E2.
Ask for help to debug why my URL fragment is not reaching katex.render.

✔️ Awesome, I've got everything!

Your file keeps its existing KaTeX setup. The render source now comes from the URL fragment.

ⓧ I'd like to double check the full code

The finished file has three important pieces.

Confirm index.html still loads the KaTeX CSS and JavaScript files from the CDN.
Confirm the first argument of katex.render is decodeURIComponent(location.hash.slice(1)).
Confirm the existing equation output element remains the second argument of katex.render.

Prove the fragment controls the equation

A second fragment proves that the page can recover a full LaTeX command. This test uses encoded backslashes and braces to produce a fraction.

Click the browser's address bar.
Replace the current fragment with #%5Cfrac%7B1%7D%7B2%7D.
Press Enter.

Before you reload, do you expect a formatted fraction or the raw percent signs to appear? The refresh checks how the fragment is decoded.

Reload the page by pressing Cmd+R on macOS or Ctrl+R on Windows.

You will see a stacked fraction with 1 above 2. You have the core sharing loop working because the link itself now carries the document.

Seeing an Error Instead of the Fraction?

Check that every percent sign in #%5Cfrac%7B1%7D%7B2%7D is followed by the same two characters shown here.
Confirm the fragment begins with one # character.
Ask for help to debug my encoded LaTeX fragment.

Your page can now render a different document from each URL. Next, you will let the page rewrite its own fragment as someone types.

Add the Link Editor

Your KaTeX page already turns an encoded URL fragment into formatted maths. Editing the address bar for every change slows down the experience.

In this step, you will add an editor that keeps the fragment in sync with each keystroke. You will also add a button that copies the current link.

In this step, get ready to:

Add a textarea that starts with the current LaTeX source.
Update the fragment whenever the editor changes.
Add a button that copies the full current URL.

Add the textarea editor

The textarea brings the decoded source onto the page. Its starting value must match the source that produced the rendered equation.

Switch back to index.html in your code editor.
Add a textarea editor beside the existing equation output.
Save index.html.
Refresh the browser tab.

You should see the textarea beside the rendered equation.

Add JavaScript initialization that exposes the textarea as editor with the current decoded source.
Save index.html.
Refresh the browser tab.

You should see the current LaTeX source inside the textarea. The rendered equation should still match it.

How does the editor get its starting value?

The page removes the leading # from location.hash.
The existing decodeURIComponent logic recovers the original LaTeX source.
The editor stores that decoded source in editor.value.

The editor is now connected, so the source in the link has a visible home on the page.

Sync each keystroke to the URL

An input event fires whenever the textarea value changes. URL encoding keeps LaTeX characters such as # or % safely inside the fragment.

Add an input handler that writes encodeURIComponent(editor.value) to location.hash before rerendering through the existing katex.render logic.
Save index.html.

Before you type, do you expect the address-bar fragment to stay fixed or change with the editor?

Refresh the browser tab.
Replace the textarea contents with x^2.

You should see the URL fragment change as you type. The equation should rerender without an address-bar edit.

What does the input handler do?

The handler reads the latest source from editor.value.
The handler converts that source with encodeURIComponent(editor.value).
The handler stores the encoded result in location.hash.
The handler passes the current source to katex.render for immediate feedback.

Editor changes not reaching the URL?

Confirm the input listener is attached to the textarea stored in editor.
Check that the handler assigns encodeURIComponent(editor.value) to location.hash.
Ask for help with the event flow by selecting help me debug my editor synchronization.

You now have a live editing loop that turns each keystroke into a shareable fragment.

Copy and reopen the link

The Clipboard API lets the page place the current link on your clipboard. The copied URL includes the fragment that stores the LaTeX source.

Add a button labelled Copy link beside the editor.
Save index.html.
Refresh the browser tab.

You should see the new Copy link button beside the editor.

Add click handling that passes the full current URL to navigator.clipboard.
Save index.html.
Refresh the browser tab.

Before you copy the link, do you think a new tab can recreate the document from the URL alone?

Click Copy link.
Open a new browser tab.
Paste the copied link into the address bar.
Press Enter.

You should see identical LaTeX source inside the editor. The rendered equation should match the original tab.

Link not copied?

Check whether your browser blocked clipboard access for the current page.
Confirm the button passes the full current URL to navigator.clipboard.
Ask for focused help by selecting help me debug the Copy link button.

That closes the sharing loop: anyone with the link can recreate your document.

Your tool now turns every edit into a reusable link. Next, you will add compressed mode so longer documents need fewer URL characters.

Compress Long Documents

Your KaTeX renderer now turns a copied URL into the same equation in a fresh tab. Longer documents create unwieldy links that are harder to share.

In this step, you'll add LZ-String from a CDN to compress the LaTeX source. Plain fragments remain compatible. A live comparison shows when compression pays off.

In this step, get ready to:

Load LZ-String in index.html.
Add a control for compressed links.
Compare plain and compressed link lengths.

Add the compression controls

Compression finds repeated patterns in a document and stores them more compactly. The page needs a control for choosing that format plus counters that reveal the size difference.

Switch back to index.html in your code editor.
Find the existing region containing the equation output.
Replace that region with the interface below immediately before your current inline script:

<main>
  <!-- Keep the rendered equation separate from the editable source. -->
  <div id="output"></div>
  <textarea id="editor" aria-label="LaTeX source"></textarea>
  <button id="copyLink" type="button">Copy link</button>
  <label>
    <input id="compressedMode" type="checkbox">
    Use compressed links
  </label>
  <!-- Compare both formats before choosing which link to share. -->
  <p>Plain link: <span id="plainLength">0</span> characters</p>
  <p>Compressed link: <span id="compressedLength">0</span> characters</p>
</main>
<script src="https://cdnjs.cloudflare.com/ajax/libs/lz-string/1.5.0/lz-string.min.js"></script>

What Did This Add?

The Use compressed links checkbox chooses which fragment format the editor writes.
The two counters expose the complete plain and compressed link lengths.
The final script tag loads the compression functions directly in the browser.

Save index.html.
Refresh the browser tab from earlier.

That gives you a visible dashboard for the size trade-off. You'll see the checkbox plus two link-length counters beneath the editor.

Don't See the New Controls?

Confirm that the new main block sits inside the page's body element. Check that your browser refreshed the saved copy of index.html.

If the layout still shows the old controls, help me check where the new HTML belongs.

Encode compressed fragments

The fragment prefix identifies how the remaining text should be decoded. A fragment beginning with c: contains compressed source. Every other fragment keeps using the plain URL-encoded format from the previous step.

Select the existing inline script that handles rendering.
Replace the contents of that script with the following code:

// Cache the interface elements used for every edit.
const editor = document.querySelector("#editor"), output = document.querySelector("#output")
const compressedMode = document.querySelector("#compressedMode"), copyButton = document.querySelector("#copyLink")
// Decode either a compressed fragment or the original plain format.
function readSource() {
  const fragment = location.hash.slice(1)
  return fragment.startsWith("c:")
    ? LZString.decompressFromEncodedURIComponent(fragment.slice(2)) || ""
    : decodeURIComponent(fragment)
}
// Render the source and expose the cost of both link formats.
function updatePage() {
  const source = readSource()
  compressedMode.checked = location.hash.slice(1).startsWith("c:")
  editor.value = source
  katex.render(source, output, { displayMode: true })
  const baseLength = location.href.split("#")[0].length + 1
  document.querySelector("#plainLength").textContent = baseLength + encodeURIComponent(source).length
  document.querySelector("#compressedLength").textContent = baseLength + 2 + LZString.compressToEncodedURIComponent(source).length
}
// Rewrite the fragment whenever the source or mode changes.
function updateHash() {
  location.hash = compressedMode.checked ? `c:${LZString.compressToEncodedURIComponent(editor.value)}` : encodeURIComponent(editor.value)
}
editor.oninput = compressedMode.onchange = updateHash
window.onhashchange = updatePage
copyButton.onclick = () => navigator.clipboard.writeText(location.href)
updatePage()

How Does Compression Work Here?

The readSource() function checks the fragment prefix before decoding the source.
The LZString.decompressFromEncodedURIComponent method restores fragments beginning with c:.
The LZString.compressToEncodedURIComponent method produces URI-safe compressed text for the address bar.
The length calculation includes the page address plus the fragment marker.

Save index.html.
Refresh the browser tab.
Select the Use compressed links checkbox.

You'll see the address fragment begin with c:. The rendered equation remains unchanged.

Does the Equation Disappear?

Confirm that the LZ-String script appears before your inline script. Check the spelling of compressedMode plus each length-counter ID.

If plain fragments work but compressed fragments do not, help me debug the compressed fragment logic.

✔️ Awesome, I've got everything!

Great. Save index.html before comparing the two link formats.

ⓧ I'd like to double check the full code

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>LaTeX Link</title>
  <!-- Load the renderer and its matching stylesheet. -->
  <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.19.0/dist/katex.min.css" integrity="sha384-3rdsX6e5mueWyoweR9NIVmtEsUkokpBT/0ALqKKIBMr9j4qhHkaIkAcGgsE6uVlp" crossorigin="anonymous">
  <script src="https://cdn.jsdelivr.net/npm/katex@0.19.0/dist/katex.min.js" integrity="sha384-QFFtAGzvvj+bfgCGxXJlNZZR1nXEZgvG8tDLCCY1F19xl20WlfTYgguB4VcNdxYk" crossorigin="anonymous"></script>
</head>
<body>
  <main>
    <!-- Keep the rendered equation separate from the editable source. -->
    <div id="output"></div>
    <textarea id="editor" aria-label="LaTeX source"></textarea>
    <button id="copyLink" type="button">Copy link</button>
    <label>
      <input id="compressedMode" type="checkbox">
      Use compressed links
    </label>
    <!-- Compare both formats before choosing which link to share. -->
    <p>Plain link: <span id="plainLength">0</span> characters</p>
    <p>Compressed link: <span id="compressedLength">0</span> characters</p>
  </main>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/lz-string/1.5.0/lz-string.min.js"></script>
  <script>
    // Cache the interface elements used for every edit.
    const editor = document.querySelector("#editor"), output = document.querySelector("#output")
    const compressedMode = document.querySelector("#compressedMode"), copyButton = document.querySelector("#copyLink")
    // Decode either a compressed fragment or the original plain format.
    function readSource() {
      const fragment = location.hash.slice(1)
      return fragment.startsWith("c:")
        ? LZString.decompressFromEncodedURIComponent(fragment.slice(2)) || ""
        : decodeURIComponent(fragment)
    }
    // Render the source and expose the cost of both link formats.
    function updatePage() {
      const source = readSource()
      compressedMode.checked = location.hash.slice(1).startsWith("c:")
      editor.value = source
      katex.render(source, output, { displayMode: true })
      const baseLength = location.href.split("#")[0].length + 1
      document.querySelector("#plainLength").textContent = baseLength + encodeURIComponent(source).length
      document.querySelector("#compressedLength").textContent = baseLength + 2 + LZString.compressToEncodedURIComponent(source).length
    }
    // Rewrite the fragment whenever the source or mode changes.
    function updateHash() {
      location.hash = compressedMode.checked ? `c:${LZString.compressToEncodedURIComponent(editor.value)}` : encodeURIComponent(editor.value)
    }
    editor.oninput = compressedMode.onchange = updateHash
    window.onhashchange = updatePage
    copyButton.onclick = () => navigator.clipboard.writeText(location.href)
    updatePage()
  </script>
</body>
</html>

Compare the link lengths

Compression becomes useful when the source contains enough repetition. A longer document makes the difference visible in the counters.

Before you test it, which counter do you expect to grow more slowly as the document gets longer?

Clear the Use compressed links checkbox.
Paste ten copies of the valid equation already in the editor.
Check the two counters to identify the shorter format.

You'll see the compressed link use fewer characters than the plain link. Repeated LaTeX commands give the compressor patterns it can shrink.

Select the Use compressed links checkbox.
Click Copy link.
Open a new browser tab.
Paste the copied link into the address bar.
Press Enter.

You've now proved that the shorter format is self-contained. You'll see the same long document render with Use compressed links selected.

Your tool can now keep long LaTeX documents inside shorter shareable links. Next, you'll give empty pages a useful starting point and turn invalid input into a clear error state.

Handle Empty and Invalid Input

Your compressed links now preserve long documents in shorter URLs. A shared link can still arrive with an empty fragment.

Half-typed LaTeX can also make KaTeX reject the current document. A damaged link can fail before rendering even begins.

In this step, you will give empty links a starter example. Rendering failures will appear in a friendly error panel.

In this step, get ready to:

Load a starter LaTeX example when the fragment is empty.
Catch decoding failures plus decompression failures plus invalid LaTeX.
Verify the empty state plus the error state plus recovery.

Load a starter example

An empty link should still demonstrate what the tool can do. A starter example gives the learner editable LaTeX as soon as the page loads.

How the empty state works

When location.hash is empty, there is no shared document to decode. The empty-fragment branch supplies a defined starter example instead.

The starter value feeds the existing editor plus rendering flow. The branch keeps the fragment empty until the learner changes the editor.

Switch back to index.html in your code editor.
Find the rendering flow that reads location.hash.
Implement the empty-fragment behavior described above before the plain-fragment branch plus the c: branch.
Save index.html.

Before you test the empty state, what do you expect the editor plus rendered area to contain?

Remove the fragment from the address bar.
Press Enter.

You should see the starter LaTeX inside the editor. You should also see its formatted equation in the rendered area.

That is the page's first graceful fallback. An empty link now becomes a useful starting point.

Starter example missing?

Confirm that the empty-fragment check runs before the plain plus compressed branches. Make sure the starter value feeds the same editor plus rendering flow as decoded content.

If the page still stays empty, help me debug the empty-fragment branch.

Catch rendering failures

A shared fragment passes through several operations before the equation reaches the screen. One guarded flow can turn a failure at any stage into the same understandable error state.

How the guarded render flow works

The guarded path decodes the URL fragment before using its contents.
A c: fragment passes through LZ-String using LZString.decompressFromEncodedURIComponent. An unusable result enters the failure state.
The call to katex.render stays inside the same guarded flow. Invalid LaTeX enters the failure state.
The failure state clears the previous output. It reveals a dedicated panel with a friendly message. The next successful render hides that panel again.

Return to index.html in your code editor.
Find the flow that decodes the fragment before calling katex.render.
Implement the guarded error experience described above in index.html.
Save index.html.
Add an unmatched opening brace to the end of the text in the editor.

You should see the friendly error panel in place of a blank rendered area. The editor should remain available for corrections.

Remove the unmatched opening brace from the editor.

Your formatted equation should return. The error panel should disappear after the successful render.

You have closed the blank-page trap. The page now explains a rendering failure without breaking the editing loop.

Error panel not appearing?

Confirm that URL decoding plus decompression plus katex.render all run inside the guarded flow. Check that the failure path reveals the panel after clearing stale output.

If the page becomes unresponsive, help me debug the guarded rendering flow.

Verify every fallback

The final check moves through the empty state. It then proves recovery from invalid LaTeX.

Before you begin, which state should appear for an empty fragment? Which state should appear for broken LaTeX?

Remove the fragment from the browser address bar.
Press Enter.

You should see the starter LaTeX in the editor. The rendered equation should appear with the error panel hidden.

Add an unmatched opening brace to the end of the editor content.

You should see the friendly error panel. The previous rendered output should be cleared.

Remove the unmatched opening brace from the editor.

You should see the formatted equation return. The error panel should be hidden again.

Strong finish. Your shared-link tool now stays useful through empty input plus invalid input plus corrected input.

Your local page is ready to share beyond your computer. Next, you will publish it with GitHub Pages so anyone can open an equation link.

Publish on GitHub Pages

Your equation-link tool now turns a URL fragment into rendered maths. Its local address still works only on your computer.

Publishing index.html to GitHub gives the page a home online. GitHub Pages turns the default branch into a public static site.

In this step, you will push your page to a GitHub repository. You will finish by opening a shared equation link on the live site.

In this step, get ready to:

Push your committed index.html to a new GitHub repository.
Publish the repository's default branch with GitHub Pages.
Open a shared live equation link in a fresh browser window.

Push the project to GitHub

A Git repository records snapshots of your project. The remote repository gives GitHub Pages access to the committed page.

Sign in to GitHub.com with your GitHub account.
Click the + icon in the top-right corner.
Select New repository.
Enter latex-equation-link in the Repository name field.
Select Public as the repository visibility.
Leave every repository initialization option cleared.
Click Create repository.

Why keep the repository empty?

Your local project already contains the page you want to publish. An empty remote repository lets you push that existing history without conflicting starter files.

Record the HTTPS remote URL shown under Quick Setup: https://github.com/your-username/latex-equation-link.git.
Switch back to the code editor from earlier.
Open its integrated terminal for the folder that contains index.html.
Create the first local snapshot by running these commands:

git init -b main
git add .
git commit -m "First commit"

What do these commands do?

The git init -b main command creates the local repository. It names the first branch main.
The git add . command stages the contents of the current folder.
The git commit -m "First commit" command saves the staged page as a versioned snapshot.

Check the final lines in the terminal output.

You should see a new commit summary that reports one file changed. Your page now has a local Git history.

Commit did not complete?

Follow the author identity instructions shown in the terminal.
Run the three commands again after Git accepts your identity.
Ask for targeted help with my first Git commit.

The local snapshot is ready. The next push connects it to the remote repository.

Your first push may ask you to sign in

Git can start an authentication flow when this computer has not pushed to GitHub before.

Complete any authentication prompt with the GitHub account that owns latex-equation-link.

Publish the local snapshot to the saved repository by running these commands:

git remote add origin [[YOUR_REPO_URL="https://github.com/your-username/latex-equation-link.git"]]
git push -u origin main

What do these commands do?

The first command connects your local repository to the remote URL. It gives that connection the name origin.
The git push -u origin main command uploads the main branch. It also sets that remote branch as the default destination for later pushes.

Return to the GitHub repository page from earlier.
Refresh the repository page.

You should see index.html in the file list. The latest commit should show First commit.

Push did not reach GitHub?

Confirm that the repository URL belongs to the account you used for authentication.
Confirm that origin points to the new latex-equation-link repository.
Get help with my GitHub push.

Deploy the default branch

The publishing source tells GitHub Pages which committed files should become the website. Your complete static page already sits at the top level of main.

Click the repository's Settings tab.
Select Pages in the sidebar.
Select Deploy from a branch from the Source dropdown under Build and deployment.
Select main from the branch dropdown.
Select the repository root from the folder dropdown.
Click Save.

The first deployment can take up to 10 minutes, so a brief wait is expected.

Wait for the deployment to finish.
Refresh the Pages settings.
Click Visit site.

You'll see the deployed editor with the starter equation rendered on the page.

Record the live URL from the address bar: https://your-username.github.io/latex-equation-link/.

The deployment is complete. Your renderer now has a public address at https://your-username.github.io/latex-equation-link/.

Live site still unavailable?

Confirm that Source is set to Deploy from a branch.
Confirm that the branch dropdown uses main.
Confirm that the folder dropdown points to the repository root.

Ask for help with my GitHub Pages deployment.

Verify a shared live link

A copied live link uses the Pages URL to load index.html. The fragment after # restores the equation in the browser.

Click inside the editor on the deployed page from earlier.
Press Space.
Press Backspace.
Click Copy link.

The address bar now includes a # fragment containing the starter document.

Before you open the copy, do you expect the fresh window to recover the same equation from the fragment?

Open a fresh private window from your browser menu.
Paste the copied link into the address bar.
Press Enter.

You'll see the same rendered equation as the deployed page. The address bar keeps the document after #.

Shared link did not restore the equation?

Use the live GitHub Pages tab as the source for the copied link.
Confirm that the copied URL contains a # fragment.
Get help with my shared equation link.

You did it. Your equation-link tool is public and every rendered document can travel inside its own shareable URL.

Secret mission

Run a Link Reliability Test

Put your live equation-link tool through a reliability test using a long document with URL-sensitive symbols. Prove that plain links preserve the document. Repeat the test with compression. Finish by recovering from invalid LaTeX.

Clean Up Your Resources

Your equation-link tool uses GitHub Pages static hosting at no ongoing cost for this project. Choose whether to keep the tool live, pause your work, or remove it entirely.

Resources you used:

GitHub repository containing your committed index.html file.
GitHub Pages deployment serving your equation-link tool.

Keep everything running

No action is needed. Choose this if you want shared equation links to keep working.

Keep the GitHub repository so your source code remains available.
Keep the GitHub Pages deployment so your live tool stays online.
Continue sharing equation links from the deployed site whenever you need them.

Pause - I'll come back to this later

A static GitHub Pages site has no local process to stop. Pausing means leaving the repository unchanged until you return.

Leave the GitHub repository unchanged.
Close the code editor when you finish working locally.
Return to the repository when you are ready to update the tool.

Delete - I don't want to use this again

Deleting the repository is the only irreversible option here. Your browser and code editor stay installed.

Open your equation-link repository on GitHub.
Use the repository navigation to open its settings page.
Go to the repository deletion area at the bottom of the settings page.
Choose the permanent repository deletion option.
Complete GitHub's confirmation prompts.
Switch back to the GitHub Pages browser tab from earlier.
Refresh the page to confirm the equation-link tool is no longer available at that address.

Deleting the repository also removes its GitHub Pages deployment. Once GitHub finishes removing the site, the shared equation links stop loading the tool.

Nice Work!

Your equation-link tool is live! You can now turn a LaTeX document into a shareable link that renders the same result on your GitHub Pages site.

You've learned how to:

Store a LaTeX document inside a URL fragment. Render formatted maths entirely in the browser.
Connect a live editor to the address bar. Create plain and compressed links. Copy a link that restores the same document in a fresh tab.
Show a starter example when a link has no document. Replace broken output with a friendly error panel. Publish the finished page with GitHub Pages.
Complete the optional Secret Mission to extend your equation-link tool further.

Ready to quiz yourself?