How to get an element's padding value using JavaScript?

javascript

getcomputedstyle

javascript-padding

css-styles

byAnton Shumikhin·Aug 26, 2024

To capture an element's padding in JavaScript, we use window.getComputedStyle. This method is workable across all modern browsers starting from IE9. Here's a quick look:

const compStyle = getComputedStyle(document.getElementById('elemId'));
console.log(compStyle.paddingTop, compStyle.paddingRight, compStyle.paddingBottom, compStyle.paddingLeft);

In this snippet, compStyle retains the computed styles, covering the padding values for each facet of the element.

Breaking down the getComputedStyle method

Computed styles are the end-result styles taken after assessing inline styles, stylesheet rules, and browser default styles. The getComputedStyle method fetches a live CSSStyleDeclaration object, encapsulating the element's styles. This means any padding set using em, rem, or percentage values is translated into pixel equivalent by getComputedStyle.

Translating the returned value

Now beieving in the power of numbers over strings, we convert the returned padding value from a string to integer/float using parseInt or parseFloat:

let paddingTop = parseInt(compStyle.paddingTop, 10); // Padding top? More like top-notch padding!

The elephant in the browser (IE8 and older)

Heads-up, getComputedStyle might give the cold shoulder to IE8 and earlier versions. So if you're working on projects supporting these browsers, consider crafting some fallback code or embracing a library that plugs these disparities.

Inline styles, the heroes within

If padding gets set inline, getting it through the element's style attribute is more straight-cut:

let paddingInline = element.style.padding; // Hey padding, why don't you make like a tree and leaf us some space?

Nevertheless, this method shows its colors only for styles applied directly via the element's style attribute, not for those flowing through external or internal CSS.

Advanced ways to get your hands on padding

We know getComputedStyle is robust, but it's not the best at breaking down individual padding values if we query element.style.padding. So here's how you can get individual padding values:

Collect them all

To dissect individual padding values to molecular level:

let style = getComputedStyle(element);
let padding = {
  top: parseFloat(style.paddingTop),
  right: parseFloat(style.paddingRight),
  bottom: parseFloat(style.paddingBottom),
  left: parseFloat(style.paddingLeft)
};

Responsive padding: Dealing with chameleons

Ever vigilant, padding might go chameleon on you depending on different screen sizes, especially if it's set with relative units or CSS media queries. Always exercise caution to derive the padding value in a responsive environment.

Cashing in on computed styles (Caching, not Typo)

For scripts feasting on getComputedStyle a bit too much, it's healthy to cache the result for a performance boost:

let cachedComputedStyle = getComputedStyle(element); // Caching, the secret sauce!
// Now use nostalgic cachedComputedStyle everywhere needed

Special notes

Shorthand properties? Overjoyed!

getComputedStyle beams even when dealing with shorthand properties, giving back individual side values.

Visual vs. layout padding

Remember, padding can be your ally or your enemy. Depending on the situation, it could either be cosmetic, giving a visual breather, or functional, affecting the flow of the document.

Apt accessibility

Changing padding without forethought could disrupt the usability and accessibility of your web page. Look out for your end-users relying on keyboard navigation or screen readers.