i have a textbox, in that i want to restrict the alphabets only, that is it will accept only numbers and special charcaters not alphabets..

i had tried the below java script ,but it will not working ....

<script type="text/javascript">
    //Function to allow only numbers to textbox
    function validate(key) {
        //getting key code of pressed key
        var keycode = (key.which) ? key.which : key.keyCode;        
        //paring pressed keycodes

        if (keyCode >= 65 && keyCode <= 90) {
            return false;
        }       
    } 
    </script>

and in the textbox

 <asp:TextBox ID="txt1" runat="server" OnTextChanged="txtoldpwd_TextChanged"
                            onkeypress="return validate(event)"></asp:TextBox>

i have a textbox, in that i want to restrict the alphabets only, that is it will accept only numbers and special charcaters not alphabets..

i had tried the below java script ,but it will not working ....

<script type="text/javascript">
    //Function to allow only numbers to textbox
    function validate(key) {
        //getting key code of pressed key
        var keycode = (key.which) ? key.which : key.keyCode;        
        //paring pressed keycodes

        if (keyCode >= 65 && keyCode <= 90) {
            return false;
        }       
    } 
    </script>

and in the textbox

 <asp:TextBox ID="txt1" runat="server" OnTextChanged="txtoldpwd_TextChanged"
                            onkeypress="return validate(event)"></asp:TextBox>

• javascript
• jquery
• c#-3.0

• 4 "it will not working" doesn't describe how the actual behaviour isn't the same as the desired behaviour. (The fact that you're returning a value in one case but not the other seems odd to me...) It's also not at all clear what this really has to do with C#. Is the expected Javascript reaching the browser? If so, it's just a Javascript issue, and you can diagnose/fix it without involving ASP.NET at all. – Jon Skeet Commented Dec 1, 2014 at 11:41
• 1. You have a typo in the if statement (keyCode instead of keycode) 2. the range 65-90 is for uppercase letters and after fixing the typo it doesn't allow to type them in, so it kind of works 3. don't use keyboard-related events for validation (doesn't prevent pasting invalid characters). – pawel Commented Dec 1, 2014 at 11:54

4 Answers 4

Write script as

<script type="text/javascript">
    function Validate(event) {
        var regex = new RegExp("^[0-9-!@#$%*?]");
        var key = String.fromCharCode(event.charCode ? event.which : event.charCode);
        if (!regex.test(key)) {
            event.preventDefault();
            return false;
        }
    }       
</script>

and call like

<asp:TextBox ID="txtcheck" onkeypress="return Validate(event);" runat="server" />

$(function(){
$('input').keypress(function(e){
var txt = String.fromCharCode(e.which);
console.log(txt + ' : ' + e.which);
if(!txt.match(/[A-Za-z+#.]/))
{
return false;
}
});
});

<script src="https://ajax.googleapis./ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="text"  />

function AllowAlphabet(evt) {
 var charCode = (evt.which) ? evt.which : event.keyCode;
 if ((charCode > 64 && charCode < 91) || (charCode > 96 && charCode < 123))
 return true;
 else
return false;
}

You can use regular expression validator. Here is

      <asp:TextBox ID="txt1" runat="server"></asp:TextBox>
<asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" ControlToValidate="txt1"
    ErrorMessage="Enter a valid number" ValidationExpression="^\d+$"></asp:RegularExpressionValidator>     

Or if you want to use JavaScript:

Try this example: http://www.codeproject./Tips/328178/Allow-only-Numeric-values-in-ASP-Text-box-control