Javascript width of div, returns 0

Question

I m trying to retrieve the width of an div for my function with javascript:

#areaDraw {
margin-top:50px;
width: 50%;
min-height: 100%;
z-index: 1000;
}

and the function:

 Event.add(window, "resize", function() {
    sketch.resize(document.getElementById("areaDraw").style.width,   window.innerHeight);
}).listener();

somehow javascript always returns 0 for the width of the div(areaDraw)

so whats wrong with:

document.getElementById("areaDraw").style.width

Answer 1

Try document.getElementById("mydiv").offsetWidth instead of .style.width