StylePropertyMap: append() method
Limited availability
This feature is not Baseline because it does not work in some of the most widely-used browsers.
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The append() method of the StylePropertyMap interface adds one or more values to the end of a list-valued CSS property's value list.
A list-valued CSS property is one whose value is a comma-separated list of terms, such as background-image or animation.
Syntax
append(property)
append(property, value1)
append(property, value1, value2)
append(property, value1, value2, /* …, */ valueN)
Parameters
property-
An identifier indicating the stylistic feature (e.g., font, width, background color) to add.
value1, …,valueN-
One or more values to add to the end of
property's value list, in the order given.
Return value
None (undefined).
Exceptions
TypeError-
Thrown if:
propertyis not a valid CSS list-valued property.- Any of
value1, …,valueNis already associated with a different property (for example, a value read from one property's entry in aStylePropertyMap, then passed toappend()for another property). - Any of
value1, …,valueNis aCSSUnparsedValueorCSSVariableReferenceValueobject. property's current value contains avar()reference.
Examples
Basic usage
This example shows an extra background image value being added to the background-image property of the element, using HTMLElement.attributeStyleMap.
// get the button element
const buttonEl = document.querySelector("button");
// append another value to the background-image property set on the attribute
buttonEl.attributeStyleMap.append(
"background-image",
"linear-gradient(180deg, blue, black)",
);
Specifications
| Specification |
|---|
| CSS Typed OM Level 1 # dom-stylepropertymap-append |