width of character to detect asian language support

http://stackoverflow.com/questions/604993/is-it-possible-to-detect-east-asian-language-support
http://stackoverflow.com/questions/118241/calculate-text-width-with-javascript
<html>
<head>
</head>
<body>
<script language="javascript" type="text/javascript">
function length_of_char(str){
    var div = document.createElement('div');
    div.style.height='auto';
    div.style.width='auto';
    div.style.visibility='hidden';
    div.style.position='absolute';
    div.style.borderWidth='0px';
    div.appendChild( document.createTextNode(str) );
    document.documentElement.appendChild(div);
    return div.clientWidth;
}
var l1= length_of_char('\u30A2');
var l2= length_of_char('\uFF71');
console.log( l1 );
console.log( l2 );
</script>
</body>
</html>