// in this
enter value
<input type="text" id="product13" name="product13" onkeyup ="isNumberKey()";">
// here it
will show output
<asp:TextBox ID="TextBox1"
runat="server"></asp:TextBox>
Script:
<script type="text/javascript">
function
isNumberKey() {
var i =
document.getElementById("product13").value.replace(/\D/g,
'');
document.getElementById("TextBox1").value = i;
}
</script>