Javascript element style

Question

I\'m curious why this one

    fdsfsd

.overlay{
    width: 100px;
    height: 200px;
    background-color:red;
}
         


        

Answer 1

The style gives access only to information which is put into elem.style. In your example style doesn’t tell anything about the margin defined in CSS. Use getComputedStyle().

var computedStyle = getComputedStyle(document.getElementsByClassName("overlay")[0], null)

alert(computedStyle.width);

jsfiddle demo