Pen Settings



CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URLs added here will be added as <link>s in order, and before the CSS in the editor. You can use the CSS from another Pen by using its URL and the proper URL extension.

+ add another resource


Babel includes JSX processing.

Add External Scripts/Pens

Any URL's added here will be added as <script>s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.

+ add another resource


Add Packages

Search for and use JavaScript packages from npm here. By selecting a package, an import statement will be added to the top of the JavaScript editor for this package.


Auto Save

If active, Pens will autosave every 30 seconds after being saved once.

Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

Format on Save

If enabled, your code will be formatted when you actively save your Pen. Note: your code becomes un-folded during formatting.

Editor Settings

Code Indentation

Want to change your Syntax Highlighting theme, Fonts and more?

Visit your global Editor Settings.


                <div class="container">
Inline MathJax

The scripts in this file allow math formulas to be written anywhere within the HTML code.  To start a formula you use either a dollar sign \$ or you can use a slash an an open parentheses "/(".  To end the inline math, you have another dollar sign or a back slash and a closing parentheses.  Enclosing in double dollar signs put the math on its own line.  Or you can use the backslash and a hard bracket "\[".

If you need to actually use a regular dollar sign in the text, then you need to 'escape' it so the page doesn't think its the start of math.  In order to escape it you use a backslash before the dollar sign.  "\\$"

<li>Dollar Signs: $y=mx+1$</li>
<li>Parenthesis: \(y=mx+2\)</li>
<li>Double Dollar Signs: $$y=mx+3$$</li>
<li>Hard Bracket: \[y=mx+5\]</li>
  <li>$\lim_{x \to \infty} \exp(‐x) = 0$</li>
  <li>$\cos (2\theta) = \cos^2 \theta ‐ \sin^2 \theta$</li>
  <li>$a \bmod b$</li>
  <li>$x \equiv a \pmod b$</li>

In a sentence
When $a \ne 0$, there are two solutions to \(ax^2 + bx + c = 0\) and they are
$$x = {-b \pm \sqrt{b^2-4ac} \over 2a}.$$