Can elements have IDs that start with numbers?

Can Elements Have IDs That Begin with Numbers?

Yes, HTML allows elements to have IDs that start with numbers. However, using such IDs can complicate CSS and JavaScript interactions.

Limitations in CSS Selectors:

Numeric IDs require escaping in CSS selectors, using a backslash () followed by the hexadecimal character code of the digit(s). For example, to select an element with the ID "12", you would use #3132.

Browser Support and Compatibility:

While modern browsers support IDs starting with numbers, using them is not recommended due to potential issues with CSS selectors.

Impact on JavaScript Interactions:

In JavaScript, elements can be retrieved using document.getElementById(). However, if the ID starts with a number, it must be enclosed in quotation marks. For example, to access an element with the ID "12", you would use document.getElementById("12").

Better Practices:

To avoid the complexities associated with numeric IDs, it is advisable to start IDs with letters and avoid using pure digits. This enhances readability, simplifies CSS and JavaScript usage, and ensures compatibility across browsers.

Example:

Here is an example using an element with the ID "12":

<div>

#12 {
  color: red;
}

document.getElementById("12").style.fontSize = "20px";

Note that the ID is quoted in JavaScript due to it starting with a number.

The above is the detailed content of Can elements have IDs that start with numbers?. For more information, please follow other related articles on the PHP Chinese website!