很简单的一JS,提示缺少对象

Question

               <table width="100%" border="0">
                    <tr>
                        <td align="right">
                            返佣总金额</td>
                        <td align="left" colspan="3">
                            <asp:TextBox ID="txtCommision" runat="server" ReadOnly="True"></asp:TextBox></td>
                    </tr>
                    <tr>
                        [b]<td align="right">
                            导游返佣</td>
                        <td align="left" colspan="3">
                            <asp:TextBox ID="txtCP" runat="server" Width="48px" 
                            onBlur="Conculate();"></asp:TextBox>% =
                            <asp:TextBox ID="txtCCommision" runat="server"></asp:TextBox>
                        </td>                 </tr>
                    <tr>
                        <td align="right">
                            旅行社返佣</td>
                        <td align="left" colspan="3">
                            <asp:TextBox ID="txtTP" runat="server" Width="48px"></asp:TextBox>% =
                            <asp:TextBox ID="txtTCommision" runat="server"></asp:TextBox>
                         </td>
                    </tr>
                    <tr>
                        <td align="center" colspan="4">
                            <asp:Button ID="Button1" runat="server" Text="保存数据" /></td>
                    </tr>
                </table>
<script type="text/javascript">
function Conculate()
{
    var ct=parseDouble(document.getElementById("txtCommision").value);
    var cp=parseDouble(document.getElementById("txtCP").value);
    var tp=100-cp;
    document.getElementById("txtTP").value=tp;
    document.getElementById("txtCCommision").value=ct*cp/100;
    document.getElementById("txtTCommision").value=ct*tp/100;
   }   
</script> 只要焦点一离开 txtCP 就提示"缺少对象"
报错是 var ct=parseDouble(document.getElementById("txtCommision").value); var cp=parseDouble(document.getElementById("txtCP").value);这两行
但只要把的值在JS中提前赋好,就不会报错了,
document.getElementById()中的值都是用复制粘贴搞上去的,
实在不懂,望JS高手赐教!!!
(调试环境 VS2005)

Answer 1

document.getElementById("txtCommision").value是空值，你可以在赋值前加个判断，如果为空就不赋值

Answer 2

 var cp=parseDouble(document.getElementById("txtCP").value);
 var tp=100-cp; 
这一段有问题，你应判断一下。
if(cp!=null)
{
 var tp=100-cp; }

Answer 3

改成了
<script type="text/javascript">
function Conculate()
{
    var txt=document.getElementById("txtCommision");
    if(txt.value!=null)
    {
          ct=parseDouble(txt.value);
          var cp=parseDouble(document.getElementById("txtCP").value);
          var tp=100-cp;
        document.getElementById("txtTP").value=tp;
        document.getElementById("txtCCommision").value=ct*cp/100;
        document.getElementById("txtTCommision").value=ct*tp/100; 
      }
     else
     {
          alert("null value");
      }
   }
        </script>
这一行 ct=parseDouble(txt.value); 报错,崩溃....再等待

Answer 4

document.getElementById("<%=txtCommision.ClientID%>").value

Answer 5

function Conculate() 
                {
                    var txt = document.getElementById("txtCommision");                    
                    if (txt.value != null && txt.value!="") {
                        ct = parseFloat(txt.value);
                        var cp = parseFloat(document.getElementById("txtCP").value);
                        var tp = 100 - cp;
                        document.getElementById("txtTP").value = tp;
                        document.getElementById("txtCCommision").value = ct * cp / 100;
                        document.getElementById("txtTCommision").value = ct * tp / 100;
                    }
                    else {
                        alert("null value");
                    }
                  }  

Answer 6

JS中没有 parseDouble()这个函数 只有 parseFloat() 及parseInt() 函数

Answer 7

       var ct=parseFloat( (document.getElementById("txtCommision").value == "") ?0.0:document.getElementById("txtCommision").value);  
    var cp=parseFloat( (document.getElementById("txtCP").value == "") ?0.0:document.getElementById("txtCP").value);    貌似只有parseFloat 方法，另外空值需要判断

Answer 8

    
        <script type="text/javascript">
        function Conculate()
        {
            var txt=document.getElementById("txtCommision"); 
            if(txt.value.length>0)
            { 
                var ct=parseFloat(txt.value); 
                var cp=parseFloat(document.getElementById("txtCP").value);
                var tp=100-cp;
                document.getElementById("txtTP").value=tp;
                document.getElementById("txtCCommision").value=ct*cp/100;
                document.getElementById("txtTCommision").value=ct*tp/100;
            }
         
          } 
        </script>