How to use the data-* attributes in HTML for custom data
Aug 02, 2025 pm 01:44 PMThe data-attribute is a feature in HTML5 used to store custom data on standard elements and does not affect the page layout; 1. Use the data-attribute to store private data on HTML elements, such as data-user-id; 2. Accessed through JavaScript's dataset attributes, such as element.dataset.userId; 3. You can also use getAttribute and setAttribute operations; 4. It can be used in CSS through attribute selector or attr() function; 5. It should avoid storing sensitive information, not abuse, or using style logic, and maintaining name semantics. These properties provide scripts with a flexible and semantic data delivery method, suitable for configuration delivery, state storage and other scenarios.
Custom data attributes in HTML, commonly known as data-*
attributes, allow you to store extra information on standard HTML elements without affecting layout or presentation. These attributes are perfect for embedding private, custom data that you can later access via JavaScript or CSS.

What Are data-* Attributes?
The data-*
attributes are part of the HTML5 specification. Any attribute that starts with data-
is considered a custom data attribute. The *
represents a name of your choice, and the value can be any string.
For example:

<div data-user-id="123" data-role="admin" data-last-login="2023-10-05"> John Doe </div>
In this example:
-
data-user-id
,data-role
, anddata-last-login
are custom data attributes. - They store additional info about the user directly in the DOM element.
These attributes are completely ignored by browsers in terms of rendering but are accessible programmatically.

How to Access data-* Attributes with JavaScript
You can retrieve and set data-*
attributes using JavaScript in two main ways: via getAttribute()
and setAttribute()
, or through the dataset
property.
Using dataset (Recommended)
The dataset
property provides a convenient way to access all data-*
attributes on an element. The key points:
-
data-*
becomesdataset.*
- Hyphens (
-
) in attribute names are converted to camelCase - Only attributes with
data-
prefix are included
Example:
<span id="product" data-product-name="Laptop" data-price="1200" data-in-stock="true"> Product Info </span>
const product = document.getElementById('product'); // Access via dataset console.log(product.dataset.productName); // "Laptop" console.log(product.dataset.price); // "1200" console.log(product.dataset.inStock); // "true" // Modify a value product.dataset.price = "1100"; // Add a new data attribute product.dataset.category = "Electronics"; // Now creates: data-category="Electronics"
Using getAttribute and setAttribute
Alternatively, you can use standard DOM methods:
console.log(product.getAttribute('data-product-name')); // "Laptop" product.setAttribute('data-discount', '10%');
This approach is more verbose but useful if you're dealing with dynamic attribute names.
Using data-* in CSS
You can also use data-*
attributes in CSS, especially with the attr()
function or attribute selectors.
Style Based on Data
[data-role="admin"] { border: 2px solid red; } [data-in-stock="false"]::after { content: " (Out of Stock)"; color: gray; }
Display Data Values
.price::after { content: attr(data-price) " USD"; }
With HTML:
<div class="price" data-price="1200"></div> <!-- Will display: 1200 USD -->
Best Practices and Tips
- Use for private data :
data-*
attributes are meant for internal use—don't use them to expose sensitive or secure information since they're visible in the source. - Avoid overuse : Don't duplicate data already available elsewhere (like in classes or IDs). Use them when the data is meaningful to scripts but not part of the visual design.
- Keep names meaningful : Use describe names, like
data-tracking-id
ordata-api-endpoint
, to improve code readingability. - Don't use for styling logic : While possible, avoid relying on
data-*
attributes for visual states—classes are better suited for that.
Summary
data-*
attributes are a clean, standardized way to embed custom data into HTML elements. They're widely supported and easy to use with JavaScript ( dataset
) and CSS. Whether you're passing configuration to a script, storing temporary state, or enhancing interaction, data-*
attributes provide a flexible and semantic solution.
Basically, if you need to attach extra info to an HTML element, and it's not presentational or security-sensitive, data-*
is the right tool.
The above is the detailed content of How to use the data-* attributes in HTML for custom data. For more information, please follow other related articles on the PHP Chinese website!

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