js计算表格列合计

<script type="text/javascript">
 String.prototype.trim=function(){return   this.replace(/(^\s*)|(\s*$)/g,   "");}  

 function Statistics() {
    
  var cols = <%=flnumber%>;  //定义多少列

  / ar rows = 4;
  
  
  var tbody1 = document.getElementById('tbody1');//数据区域
  var tbody2 = document.getElementById('tbody2');//统计区域
  
  var trs = tbody1.getElementsByTagName('tr');
  var results = new Array();
  for(var i = 0; i < trs.length; i++){
   var cells = trs[i].cells;
   results[i] = new Array();
   for(var j = 0; j < cells.length; j++){
         if(cells[j].innerHTML.trim() == "" || isNaN(cells[j].innerHTML.trim())){
          results[i][j] = 0;
         } else {
          results[i][j] = parseFloat(cells[j].innerHTML.trim());
        }
     }
  }

  //开始统计...
  var tr = document.createElement("tr");
  var td_1 = document.createElement("td");
  var td_2 = document.createElement("td");
   td_1.innerHTML = "合 &nbsp; 计";
   td_2.innerHTML = "&nbsp;";
   tr.appendChild(td_1);
   tr.appendChild(td_2);
  for(var i = 2; i < (cols+2); i++) {
   var td = document.createElement("td");
   td.className = "mainConTable";
   if(i != 0 && i != 1) {
    var st = 0;
    for(var j = 0; j < trs.length; j++){
      st += results[j][i];
    }
    td.innerHTML = st;
   }
   tr.appendChild(td);
  }
  tbody2.appendChild(tr);
  
  }
  
  Statistics();
</script>