Determine html element width without jquery

getElementWidth.js

// Function to determine the width of any element in pixel:
getElementWidth = function (node) {
  var ow = node.offsetWidth,
      cs = node.currentStyle && node.currentStyle["width"] 
           || getComputedStyle && getComputedStyle(node, null).getPropertyValue("width"),
      result = parseFloat(ow || cs);
  if (cs && cs.match(/%/))
    return (parseFloat(cs) / 100) * getElementWidth(node.parentNode);
  if (isNaN(result) || result == 0)
    return getElementWidth(node.parentNode);
  return result;
}