This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The CSSStyleDeclaration.getPropertyPriority() method interface returns a string that provides all explicitly set priorities on the CSS property.
getPropertyPriority(property)
propertyA string representing the property name to be checked.
A string that represents the priority (e.g., "important") if one exists. If none exists, returns the empty string.
The following JavaScript code checks whether margin is marked as important in a CSS selector rule:
const declaration = document.styleSheets[0].cssRules[0].style;
const isImportant = declaration.getPropertyPriority("margin") === "important";
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Opera | Safari | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | WebView Android | WebView on iOS | |
getPropertyPriority |
1 | 12 | 1 | ≤12.1 | 1 | 18 | 4 | ≤12.1 | 1 | 1.0 | 4.4 | 1 |
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https://developer.mozilla.org/en-US/docs/Web/API/CSSStyleDeclaration/getPropertyPriority