js计算字符个数，包括中文

<SCRIPT language="JavaScript">
 <!--
 function countCharacters(str){
    var totalCount = 0; 
    for (var i=0; i<str.length; i++) { 
        var c = str.charCodeAt(i); 
    if ((c >= 0x0001 && c <= 0x007e) || (0xff60<=c && c<=0xff9f)) { 
           totalCount++; 
        }else {    
            totalCount+=2; 
        } 
    }
  // alert(totalCount);
    return totalCount;
}
//-->
</SCRIPT>