只能输入数字js代码

<script language="javascript" type="text/javascript">
function myKeyDown() {
var k = window.event.keyCode;
if ((k == 46) || (k == 8)  || (k == 110) || (k >= 48 && k <= 57) || (k >= 96 && k <= 105) || (k >= 37 && k <= 40)){ }
else if (k == 13) {window.event.keyCode = 9;}
else {window.event.returnValue = false;}
}
</script>

 

asp.net 中调用 
         <input runat="server" name="jiage2" id="jiage2" onkeydown="myKeyDown()" type="text" size="10" style="width:40px;"/>