/Web APIs

StylePropertyMapReadOnly: size property

The size read-only property of the StylePropertyMapReadOnly interface returns an unsigned long integer containing the size of the StylePropertyMapReadOnly object.


An unsigned long integer.


Here we use the size property to return the total entries within the button elements computedStyleMap.


// grab our element
const buttonEl = document.querySelector("button");

// we can retrieve all computed styles with `computedStyleMap`
const allComputedStyles = buttonEl.computedStyleMap();

// use size to get the total styles within the map
const amountStyles = allComputedStyles.size;
console.log(amountStyles); // logs 338


Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
size 66 79 No No 53 16.4 66 66 No 47 16.4 9.0

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