js 获取浮点的整数部分

<script type="text/javascript">
function LTrim(s) {
var i = 0;
    var length = s.length;
    alert("s="+s);
    alert("length=="+length);
    var retval = "" ;
    for (i=0;i<length;i++){
  if (retval=="")
  {
         if (s.charAt(i)!=' '){
            retval = retval + s.charAt(i);
         }
      }else{
        retval = retval + s.charAt(i);
      }
    }
    alert("retval="+retval);
    return retval;
}
function RTrim(s) {
  var i = 0;
    var length = s.length;
    var retval = "" ;
    for (i=0;i<length;i++){
      if (retval==""){
        if (s.charAt(length-i-1)!=' '){
          retval = s.charAt(length-i-1) + retval;
        }
      }else{
        retval = s.charAt(length-i-1) + retval;
      }
    }
    return retval; 
}
function Trim(s) {
s = LTrim(s);
    s = RTrim(s);
    return s;
}
function ji() {
var b = document.forms["from1"].stockKind.value;
alert(b.length);
alert("b is:"+b);
var s =(Math.floor(b/100));

alert("s is:"+s)

return document.forms["from1"].stockType.value = s;
}
</script>