function NumOnly(var1) {
var num = document.getElementById(var1).value;
var dot = 0;
for (n = 0; n < num.length; n++) {
digit = num.charCodeAt(n) >= 48 && num.charCodeAt(n) <= 57 || num.charCodeAt(n) == 46 || num.charCodeAt(n) == 45;
if (!digit) {
alert('Enter Numbers Only');
}
}
document.getElementById('<%=txtMobile.ClientID %>').value = "";
document.getElementById(var1).focus();
}
or
Only Number validation in Textbox of ASP.NET Using Regular Expression validator
Only numbers can enter into that Textbox
We can use Regular expression validator for this:
In the validation expression property keep ^\d+$.
<asp:TextBox ID="TextBox1" runat="server" Style="z-index: 100; left: 259px; position: absolute;
top: 283px" ValidationGroup="check"></asp:TextBox>
<asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" ControlToValidate="TextBox1"
ErrorMessage="Please Enter Only Numbers" Style="z-index: 101; left: 424px; position: absolute;
top: 285px" ValidationExpression="^\d+$" ValidationGroup="check"></asp:RegularExpressionValidator>
For entering alpha numeric only
<script type="text/javascript">
function checkkey(obj)
{ var re = /^[a-zA-Z_0-9]$/;
alert(re.test(obj.value));
if (! re.test(obj.value))
{ alert("Please enter alphanumeric only");
}
}
</script>