clientWidth and clientHeight in JavaScript

Using clientWidth and clientHeight you’re able to get the pixel dimensions of an HTML element. The dimensions are calculated using the dimensions of content inside the HTML element, along with the padding.

Using clientWidth and clientHeight

<div id="foo">
  Hello World
</div>

const clientWidth = document.querySelector('#foo').clientWidth;
const clientHeight = document.querySelector('#foo').clientHeight;

Learning Exercises

As an exercise, try calculating the value of clientWidth and clientHeight of the following HTML element:

/**********************************************
 **  If the HTML element is <div id="foo"/>  **
 **********************************************/
const clientWidth = document.querySelector('div#foo').clientWidth;
const clientHeight = document.querySelector('div#foo').clientHeight;
console.log(clientWidth, clientHeight);
// --> 200, 100

How was it calculated? Add the padding, with the content inside the HTML element, and ignore the margins and borders:

(10 + 50) + 140   // clientWidth === 200
(30) + 70         // clientHeight === 100

Let’s try another! Try calculating the clientWidth and clientHeight of this HTML element:

(10 + 10) + 230   // clientWidth === 250
(30 + 20) + 70    // clientHeight === 120

Notes

• Block-level: clientWidth and clientHeight does NOT work with inline HTML elements (like span, em, or a). It’ll just return 0!
• Rounded Values: Values are rounded to the nearest integer. If you need more precise values use getBoundingClientRect()
• Read-Only: You can’t assign a new value to change the dimensions of the HTML element. For example this doesn’t do anything: someElement.clientWidth = 30

clientWidth and clientHeight are supported on all major desktop and mobile browsers.

See the official W3C specs for detailed information about clientWidth and clientHeight.