js计算一个字符中包括中英文的长度，中文占2个字符，汉子和英文占1个字符

 <script type="text/javascript">

  window.onload = function(){

 function getByteLen(val) {  

           var len = 0;            

           for (var i = 0; i < val.length; i++) {

                      var a = val.charAt(i);   

                      if (a.match(/[^\x00-\xff]/ig) != null){   

                             len += 2;             

                      }else{      

                            len += 1;             

                   }        

            }            

        return len;   

    }     

     alert(getByteLen('妈2ds'));    

}

</script>