判断输入为数字
<tr>  
     <td> 部门: </td>  
     <td   colspan= "3 ">  
        <input   type= "checkbox "   name= "codepts <%=i+1%>  "   value= " <%=TSysDept.getDeptid()%>  ">  
        <input   name= "copercent_ <%=TSysDept.getDeptid()   %>  "   class= "in "   size= "5 "   value= " "   onpropertychange= "sumNum(this) ">  
        <input   type= "hidden "   name= "porderd_ <%=TSysDept.getDeptid()   %>  "   value= " <%=porderd   %>  ">  
     </td>  
  </tr>    
 怎样判断输入为数字 
 onpropertychange= "sumNum(this)   这个脚本应该怎么实现? 
------解决方案--------------------function sumNum(obj) 
 { 
    var num=obj.value; 
    if(!num.match(/^[1-9](\d*)?(\.[\d]+)?$/)) 
    { 
        event.keyCode=0; 
        event.returnValue=0; 
    } 
 }