js实现文本框只能输入数字

<script language="javascript" type="text/javascript">
function checkNumber(e,strid,msg)
{
   
    var key = window.event ? e.keyCode : e.which;
   
    var keychar = String.fromCharCode(key);
   
    var el = document.getElementById(strid);
    var msg = document.getElementById(msg);
   
    reg = /\d/;
   
    var result = reg.test(keychar);
   
    if(!result)
    {
   
    el.className = "warn";

    
    msg.innerHTML = "只能输入数字";
   
    return false;
   
    }
   
    else
    {
   
    el.className = "";
   
    msg.innerHTML = "";
   
    return true;
   
    }
   
}
</script>

 

调用

<input type="text" id="gNum" onkeypress="return checkNumber(event,'gNum','gmsg');" style="height:20px; width:150px;"/><span id="gmsg" style="color:Red;"></span>

 

方法2：

                         <asp:TextBox ID="txtNewPageIndex" runat="server" Width="50px"  onkeypress="return isNumberKey(this)"></asp:TextBox>
                         <script language= "javascript" type="text/javascript">
                            function isNumberKey(evt)
                            {
                             var charCode = (evt.which) ? evt.which : event.keyCode
                             if (charCode > 31 && (charCode < 48 || charCode > 57))
                             {
                                return false;
                             }
                             return true;
                            }                                                         
                        </script>