StylePropertyMapReadOnly.get() - Web APIs 编辑

Experimental

This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The get() method of the StylePropertyMapReadOnly interface returns a CSSStyleValue object for the first value of the specified property.

Syntax

var declarationBlock = StylePropertyMapReadOnly.get(property)

Parameters

property

The name of the property to retrieve the value of.

Return value

A CSSStyleValue object.

Examples

Let's get just a few properties and values. Let's start by creating a link inside a paragraph in our HTML, and adding a definition list which we will populate with JavaScript:

<p>
   <a href="https://example.com">Link</a>
</p>
<dl id="results"></dl>

We add a bit of CSS, including a custom property and an inhertable property:

p {
  font-weight: bold;
}
a {
   --colour: red;
   color: var(--colour);
}

We use the Element's computedStyleMap() to return a StylePropertyMapReadOnly object. We create an array of properties of interest and use the StylePropertyMapReadOnly's get() method to get only those values.

// get the element
const myElement = document.querySelector('a');

// Retrieve all computed styles with computedStyleMap()
const styleMap = myElement.computedStyleMap();

// get the <dl> we'll be populating
const stylesList = document.querySelector('#results');

// array of properties we're interested in
const ofInterest = ['font-weight', 'border-left-color', 'color', '--colour'];

// iterate over our properties of interest
for ( let i = 0; i < ofInterest.length; i++ ) {

  // properties
  const cssProperty = document.createElement('dt');
  cssProperty.innerText = ofInterest[i];
  stylesList.appendChild(cssProperty);

  // values
  const cssValue = document.createElement('dd');
  // use get() to find the value
  cssValue.innerText = styleMap.get(ofInterest[i]);
  stylesList.appendChild(cssValue);
}

Specifications

Browser compatibility

BCD tables only load in the browser

See Also

• CSS Typed Object Model API
• Learning Houdini: the CSS Typed Object Model