real image width with javascript

1// width in pixels
2function setImagesWidth(id, width)
3{
4    var images = document.getElementById(id).getElementsByTagName("img");
5    var newWidth = width + "px";
6    for (var i = 0; i < images.length; ++i)
7    {
8        if (images[i].clientWidth > width)
9        {
10            images[i].style.width = newWidth;
11        }                       
12    }
13}
14