JavaScript 自动在表格前面增加序号

    <script language="javascript" type="text/javascript">  
        window.onload = function(){  
            var oTable = document.getElementById("num");  
            for(var i=0;i<oTable.rows.length;i++){  
            oTable.rows[i].cells[0].innerHTML = (i+1);  
        }  
    }  
    </script>  
  
注意：要在table中添加id才能生效：<tbody id="num">