CSSValue
readonly unsigned long length
The number of CSSValue objects in this array.
item( )
Returns the CSSValue object at the specified position in the array, or null if the specified position is negative or if it is greater than or equal to length.
This interface represents an array of CSSValue objects and is itself a type of CSSValue. The item( ) method can be used to retrieve the CSSValue object at a specified position, but in JavaScript, it is easier to simply index the array using standard square-bracket notation.
The order of CSSValue objects in a CSSValueList array is the order in which they appear in the CSS style declaration. Some CSS attributes whose value is a CSSValueList may also have the value none. This special value translates into a CSSValueList object with a length of 0.