Measuring Element Height with JavaScript and jQuery

When developing web applications, it’s often necessary to determine the rendered height of an HTML element. This is particularly useful for dynamic layouts, responsive design, and implementing various interactive features. This tutorial explains how to accurately measure element height using both vanilla JavaScript and the popular jQuery library.

Understanding Rendered Height

The "rendered height" refers to the actual height of an element as it’s displayed on the screen, taking into account its content, padding, borders, and potentially scrollbars. It’s different from the height explicitly set in CSS, as the rendered height adapts to the element’s content.

Using Vanilla JavaScript

JavaScript provides several properties to retrieve different measurements of an element’s height:

• clientHeight: Returns the inner height of an element in pixels. This includes the height of the content and any vertical padding, but excludes borders, margins, and scrollbars.
• offsetHeight: Returns the outer height of an element in pixels. This includes the height of the content, vertical padding, and top and bottom borders. It excludes margins.
• scrollHeight: Returns the total height of the content, including any content not visible due to overflow (e.g., scrollable content). It includes padding and borders. If the element doesn’t overflow, scrollHeight will equal clientHeight.
• getBoundingClientRect().height: Returns the size of an element and its position relative to the viewport. This method provides a more accurate and consistent measurement, especially when dealing with transformations or complex layouts.

Here’s how to use these properties:

const element = document.getElementById('myDiv');

const clientHeight = element.clientHeight;
const offsetHeight = element.offsetHeight;
const scrollHeight = element.scrollHeight;
const rectHeight = element.getBoundingClientRect().height;

console.log('clientHeight:', clientHeight);
console.log('offsetHeight:', offsetHeight);
console.log('scrollHeight:', scrollHeight);
console.log('getBoundingClientRect().height:', rectHeight);

Choose the property that best suits your specific needs based on whether you need to include padding, borders, or scrollable content in the measurement.

Using jQuery

jQuery simplifies the process of getting element height with a few convenient methods:

• .height(): Returns the inner height of the element, equivalent to clientHeight in vanilla JavaScript. It measures the height of the content plus padding, excluding borders and margins.
• .innerHeight(): Returns the height of the element including padding, but excluding borders and margins.
• .outerHeight(): Returns the total height of the element, including padding and borders.
• .outerHeight(true): Returns the total height of the element including padding, borders, and margins.

Here’s how to use these methods:

const element = $('#myDiv');

const height = element.height();
const innerHeight = element.innerHeight();
const outerHeight = element.outerHeight();
const outerHeightWithMargin = element.outerHeight(true);

console.log('height:', height);
console.log('innerHeight:', innerHeight);
console.log('outerHeight:', outerHeight);
console.log('outerHeight(true):', outerHeightWithMargin);

jQuery’s methods provide a concise and readable way to measure element height, particularly when working within a jQuery-based project.

Choosing the Right Method

| Method | Includes Content | Includes Padding | Includes Border | Includes Margin |
| ————————— | —————- | —————- | ————— | ————– |
| clientHeight / .height()| Yes | Yes | No | No |
| offsetHeight / .innerHeight()| Yes | Yes | Yes | No |
| scrollHeight | Yes | Yes | Yes | No |
| .outerHeight() | Yes | Yes | Yes | No |
| .outerHeight(true) | Yes | Yes | Yes | Yes |
| getBoundingClientRect().height | Yes | Yes | Yes | No |

Consider the specific requirements of your application when choosing the appropriate method. If you need to account for borders and margins, use .outerHeight(true) or offsetHeight. If you only need the content and padding height, .height() or clientHeight is sufficient. getBoundingClientRect().height provides a reliable cross-browser solution.