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HTML

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HTML preprocessors can make writing HTML more powerful or convenient. For instance, Markdown is designed to be easier to write and read for text documents and you could write a loop in Pug.

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Insecure Resource

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CSS

About CSS Preprocessors

CSS preprocessors help make authoring CSS easier. All of them offer things like variables and mixins to provide convenient abstractions.

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CSS Base

About CSS Base

It's a common practice to apply CSS to a page that styles elements such that they are consistent across all browsers. We offer two of the most popular choices: normalize.css and a reset. Or, choose Neither and nothing will be applied.

Vendor Prefixing

About Vendor Prefixing

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JavaScript

About JavaScript Preprocessors

JavaScript preprocessors can help make authoring JavaScript easier and more convenient.

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Babel includes JSX processing.

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Packages

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HTML 

              
                <h1>dialog focus test</h2>

<h2>Dialog with no interactive element</h2>

<button>demo 1</button>

<dialog>
  <h1>Demo 1</h2>
</dialog>

<h2>Dialog with interactive elements</h2>

<button>demo 2</button>

<dialog>
  <h1>Demo 2</h2>
  
  <button>First focusable element</button>
  <a href="#">Last focusable element</a>
</dialog>

<h2>Dialog with interactive elements and close button</h2>

<button>demo 3</button>

<dialog>
  <form method="dialog">
    <button>close</button>
  </form>
  
  <h1>Demo 3</h2>
  
  <button>First focusable element</button>
  <a href="#">Last focusable element</a>
</dialog>

<h2>Dialog with interactive elements and close button</h2>

<button>demo 4</button>

<dialog>
  <h1>Demo 4</h2>
  
  <button>First focusable element</button>
  <a href="#">Last focusable element</a>
  
  <form method="dialog">
    <button>close</button>
  </form>
</dialog>

<h2>Dialog without interactive elements and autofocus on dialog</h2>

<button>demo 5</button>

<dialog autofocus>
  <h1>Demo 5</h2>
</dialog>


<h2>Dialog with interactive elements and autofocus on dialog</h2>

<button>demo 6</button>

<dialog autofocus>
  <h1>Demo 6</h2>
 
  <button>First focusable element</button>
  <a href="#">Last focusable element</a>
</dialog>

<h2>Dialog with autofocus on last interactive element</h2>

<button>demo 7</button>

<dialog>
  <h1>Demo 7</h2>
 
  <button>First focusable element</button>
  <a href="#" autofocus>Last focusable element</a>
</dialog>

<h2>Dialog with tabindex and no interactive element</h2>

<button>demo 8</button>

<dialog tabindex="-1">
  <h1>Demo 8</h2>
</dialog>

<h2>Dialog with tabindex and interactive elements</h2>

<button>demo 9</button>

<dialog tabindex="-1">
  <h1>Demo 9</h2>

  <button>First focusable element</button>
  <a href="#">Last focusable element</a>
</dialog>


<h2>Dialog with tabindex, autofocus, and interactive elements</h2>

<button>demo 10</button>

<dialog tabindex="-1" autofocus>
  <h1>Demo 10</h2>

  <button>First focusable element</button>
  <a href="#">Last focusable element</a>
</dialog>

<h2>Dialog with tabindex, focus(), and interactive elements</h2>

<button class="focus">demo 11</button>

<dialog tabindex="-1">
  <h1>Demo 11</h2>

  <button>First focusable element</button>
  <a href="#">Last focusable element</a>
</dialog>
!

CSS 

              
                :focus {
  outline: 5px solid hotpink;
}
!

JS 

              
                document.addEventListener('click', e => {
  const button = e.target;
  if (button.closest('button')) {
    const dialog = button.nextElementSibling;
    dialog.showModal()
    
    if (button.classList.contains('focus')) {
      dialog.focus()
    }
  }
})
!
999px

Console