How do I retrieve an HTML element's actual width and height?

To retrieve an HTML element’s actual rendered width and height, you have multiple approaches in vanilla JavaScript and jQuery. Here are the most common methods:

1. offsetWidth and offsetHeight

const element = document.getElementById('myElement');
const width = element.offsetWidth;
const height = element.offsetHeight;

console.log(width, height);

• Includes padding, the element’s borders, and vertical scrollbars (if any), but not margins.

2. clientWidth and clientHeight

const width = element.clientWidth;
const height = element.clientHeight;

• Includes padding but excludes borders, margins, and scrollbars.

3. getBoundingClientRect()

const rect = element.getBoundingClientRect();
const width = rect.width;
const height = rect.height;

• Returns a DOMRect object containing the element’s size and its position relative to the viewport.
• Especially handy when you need both position (e.g., left/top) and size (width/height).

4. jQuery Methods

If you’re using jQuery:

const $el = $('#myElement');
const width = $el.width();       // Content width (no padding, borders, or margin)
const height = $el.height();

const outerW = $el.outerWidth(); // Includes padding + border
const outerH = $el.outerHeight();

console.log(width, height, outerW, outerH);

• outerWidth(true) and outerHeight(true) can also include margins.

Best Practices

1. Decide if you need borders, padding, or margins in the measurement.
2. offsetWidth/offsetHeight is a quick go-to for an element’s “box” size.
3. If you need precise location on the screen, or if the element might be transformed (e.g., scaled), use getBoundingClientRect().

Enhance Your JavaScript Skills

To deepen your knowledge of DOM manipulation and core JavaScript concepts, consider these courses from DesignGurus.io:

• Grokking JavaScript Fundamentals
• Grokking the Coding Interview: Patterns for Coding Questions

You can also explore the DesignGurus.io YouTube channel for additional tutorials and discussions on front-end development, coding interview tips, and software design.