Javascript validatations for letters or numbers only

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I have created a web form with different text boxes with C# code at the back. So I want to use JavaScript to validate some text boxes.

I want a text box to allow only numbers and when you type letters it must highlight the text boxes into red and show an error message (Please Enter Numbers only).

I want a text box to allow letters and when you type letters it must highlight the text boxes in red and show an error message (Please Letters only) .

Below is the code I have:

<script language="javascript" type="text/javascript">

function numeralsOnlyNeeded(evt) {
    evt = (evt) ? evt : event;
    var charCode = (evt.charCode) ? evt.charCode : ((evt.keyCode) ? evt.keyCode :
   ((evt.which) ? evt.which : 0));
    if (charCode > 31 && (charCode < 48 || charCode > 57)) {
        alert("Enter numbers only in this field.");
        return false;
    }
    return true;
}

function lettersOnlyNeeded(evt) {
    evt = (evt) ? evt : event;
    var charCode = (evt.charCode) ? evt.charCode : ((evt.keyCode) ? evt.keyCode :
  ((evt.which) ? evt.which : 0));
    if (charCode > 31 && (charCode < 65 || charCode > 90) &&
    (charCode < 97 || charCode > 122)) {
        alert("Enter letters only.");
        return false;
    }
    return true;
}

Posted 6-Aug-13 22:31pm

Nkhanedzeni

Updated 6-Aug-13 22:47pm

Dennis C. Dietrich

v2

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Thanks7872 · Answer 1 · 2013-08-06T22:44:00

Solution 1

You can make use of some thing like below.No need to do it with javascript if you want so.

C#

<asp:textbox id="TextBox1" runat="server" ></asp:textbox>

C#

<asp:regularexpressionvalidator id="RegularExpressionValidator1" runat="server" errormessage="Enter alphnumeric values only" controltovalidate="TextBox1" ValidationExpression="^[0-9]\d*(\.\d+)?$" ></asp:regularexpressionvalidator>

use ValidationExpression="^[a-zA-Z]+$" for alpha. values only.

Regards..:laugh:

Posted 6-Aug-13 22:44pm

Thanks7872

Updated 6-Aug-13 23:01pm

v5

Comments

Nkhanedzeni 7-Aug-13 4:58am

I have used for numeric but it keeps on showing error message for both numbers and letters

Thanks7872 7-Aug-13 5:01am

Try it now.If you copy paste the above code,the text box will allow you to enter only 0-9. And if you replace the validation expression than it will allow letters only.

Nkhanedzeni 7-Aug-13 5:07am

thanks now working....don't u know how to make it change color to red if it is invalid character?

Thanks7872 7-Aug-13 5:09am

http://www.aspsnippets.com/Blue/Articles/Change-Background-and-Border-Color-of-Invalid-Controls-when-Validation-fails-in-ASP.Net.aspx

refer this link it might be helpful. You can accept this answer if it helped you.

**Nirav Prabtani** · Answer 2 · 2013-08-06T22:58:00

Try this...:)

XML

<script type="text/javascript" language="javascript">
        function validateNumbersOnly(e) {
            var unicode = e.charCode ? e.charCode : e.keyCode;
            if ((unicode == 8) || (unicode == 9) || (unicode > 47 && unicode < 58)) {
                return true;
            }
            else {

                window.alert("This field accepts only Numbers");
                return false;
            }
        }
    </script>

Reference:
how to validate textbox only for number? and not allow empty[^]

[Edit member="Tadit"]
Link text added to reflect the article title.
[/Edit]

Dev parmar · Answer 3 · 2013-08-06T23:08:00

Solution 3

Try this link. It will help you.
Javascript validations for Email,Phone no and allow only characters, spaces, numbers in asp.net[^].

[Edit member="Tadit"]
Link text added to reflect the article title.
[/Edit]

Posted 6-Aug-13 23:08pm

Dev parmar

Updated 6-Aug-13 23:47pm

v2

sandy reddy · Answer 4 · 2013-08-07T00:58:00

$(document).ready(function () {
$(".numberinput").forceNumeric();
});

// forceNumeric() plug-in implementation

jQuery.fn.forceNumeric = function () {

return this.each(function () {
$(this).keydown(function (e) {
var key = e.which || e.keyCode;

if (!e.shiftKey && !e.altKey && !e.ctrlKey &&
// numbers
key >= 48 && key <= 57 ||
// Numeric keypad
key >= 96 && key <= 105 ||
// comma, period and minus, . on keypad
key == 190 || key == 188 || key == 109 || key == 110 ||
// Backspace and Tab and Enter
key == 8 || key == 9 || key == 13 ||
// Home and End
key == 35 || key == 36 ||
// left and right arrows
key == 37 || key == 39 ||
// Del and Ins
key == 46 || key == 45) {
return true;
}
alert("Please Enter Numbers Only.");
return false;
});
});
}

--Then Call that numberinput Class in textbox

<asp:textbox id="TextBox1" cssclass="numberinput" runat="server" xmlns:asp="#unknown">

Javascript validatations for letters or numbers only

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