Some HTML attributes belong to one particular tag. A global attribute can be written on many different HTML elements. is is one of them, and it helps with identifies a customized built-in custom element.
What is changes
Identifies a customized built-in custom element. You attach it to an opening HTML tag, usually beside other attributes.
Global does not mean the browser handles it identically on every element. Its usefulness still depends on the element, surrounding markup, accessibility requirements, and browser support.
Example in a real page
<section>
<button is="fancy-button" type="button">Open</button>
</section>What to notice
Find is in the opening tag. Its position among other attributes does not change its meaning; the name and value (or mere presence, for boolean attributes) are what matter.
Requires a registered customized built-in and support is not uniform across browsers.
Using it in your projects
Start with the simplest HTML that works. Add this attribute when your page actually needs identifies a customized built-in custom element. If changing the attribute does not visibly change the page, inspect how the browser or accessibility tree uses it rather than assuming the code failed.
For example, an attribute may give information to keyboard users, screen readers, a JavaScript component, or a stylesheet without changing the appearance of text.
Mini exercise
Copy the example into a test page. Remove is, check the result, then restore it. Describe exactly what changed—and what stayed the same.
Common Beginner Mistakes
- Requires a registered customized built-in and support is not uniform across browsers.
- Assuming every global attribute is appropriate on every tag without checking the context.
- Using a browser hint as if it enforces security or saves data automatically.
Key Takeaways
is: Identifies a customized built-in custom element.- Requires a registered customized built-in and support is not uniform across browsers.
- Prefer clear native HTML, and test features that depend on browser support.