CSSStyleDeclaration length Property

lengthThe property returns an integer representing the number of style declarations in this CSS declaration block.

Syntax:

element.style.length

Example

var elem = document.getElementById("s1");
var x = elem.style.length;

All browsers fully support the length property:

Property
length	Yes	Yes	Yes	Yes	Yes

Return Value:	An integer that provides the number of styles explicitly set on the parent element of the example
DOM Version:	CSS Object Model