Go4Expert

Go4Expert (http://www.go4expert.com/)
-   JavaScript and AJAX (http://www.go4expert.com/articles/javascript-tutorials/)
-   -   Allow Only Numbers in a Textbox (http://www.go4expert.com/articles/allow-textbox-t2359/)

pradeep 27Dec2006 17:45

Allow Only Numbers in a Textbox
 
Sometimes we need the user to enter only numbers in a text field, so I have some up with a small piece of JavaScript to do exactly that. It works for both IE and Firefox.

Code: JavaScript

function onlyNumbers(evt)
{
    var e = event || evt; // for trans-browser compatibility
    var charCode = e.which || e.keyCode;

    if (charCode > 31 && (charCode < 48 || charCode > 57))
        return false;

    return true;

}

Example Usage:
HTML Code:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE>Allow Only Numbers
</HEAD>

<BODY>
<script language="JavaScript">
function onlyNumbers(evt)
{
        var e = event || evt; // for trans-browser compatibility
        var charCode = e.which || e.keyCode;

        if (charCode > 31 && (charCode < 48 || charCode > 57))
                return false;

        return true;

}
</script>
<input type="text" onkeypress="return onlyNumbers();">
</BODY>
</HTML>


vikas 6Jun2007 12:46

Re: Allow Only Numbers in a Textbox
 
thanks for this but u must mention the comments as much as possible so that other readers could eaisily get this. thx again

Vivid 13Jun2007 22:15

Re: Allow Only Numbers in a Textbox
 
Is there any way to add the ability to enter in the "-" character as well. I think it is key code 109 or 189. I can't seem to get it to accept only numbers and this one extra character.

shabbir 14Jun2007 08:56

Re: Allow Only Numbers in a Textbox
 
I am not a JS expert but you need to edit the condition
Code:

if (charCode > 31 && (charCode < 48 || charCode > 57))
so that when its 109 or 189 then it does not return false.

pradeep 14Jun2007 12:20

Re: Allow Only Numbers in a Textbox
 
Shabbir is right you just have to modify the condition to suit your needs, e.g.

Code: Javascript

if (charCode > 31 && ((charCode < 48 || charCode > 57) || charCode !=109))
  return false;


That should do it!

Darkness1337 14Jun2007 14:40

Re: Allow Only Numbers in a Textbox
 
wow, really good!
thanx a lot! :) this helps to get me some more marks on my web designing course:D lol

Iona 23Aug2008 21:19

Re: Allow Only Numbers in a Textbox
 
Not so smart. This doesn't allow for the shift key being pressed, so allows any of !"$%^&*() as well as any numeric.

Obviously (??) the onKeyDown etc doesnt detect Shift1 etc.

So as a validation before assigning to a numeric field then this just doesnt work.

Iona 23Aug2008 22:41

Re: Allow Only Numbers in a Textbox
 
:pleased:
The problem with the shift key can be fixed as follows :
{
var e = event || evt; // for trans-browser compatibility
var charCode = e.which || e.keyCode;

if (charCode > 31 && (charCode < 48 || charCode > 57))
return false;
if (e.shiftkey) return false;
return true;

}
The down side of this is that it efectively disables the numeric key pay because the Num Lock sets the shift key.

You probably need to extend the numeric character set tested for to include a decimal point . or , depending upon convention, the thousand marker , and + and - to detect signs and on occasions the currency symbols such as $ etc

darksemo 2Mar2009 20:11

Re: Allow Only Numbers in a Textbox
 
Helloo,
I'm not a javascript expert also, but this function has a parameter and we when we called it down , it doesn't talk any parameters . How Come?:thinking:

gkumar 19Jun2009 15:40

Re: Allow Only Numbers in a Textbox
 
In this example we can allow Only Numbers in a Textbox.
HTML Code:

<HTML>
  <HEAD>
  <SCRIPT language=Javascript>
      <!--
      function isNumberKey(evt)
      {
        var charCode = (evt.which) ? evt.which : event.keyCode
        if (charCode >
31 && (charCode < 48 || charCode > 57))
            return false;

        return true;
      }
      //-->

  </SCRIPT>
  </HEAD>
  <BODY>
      <INPUT id="txtChar" onkeypress="return isNumberKey(event)" type="text" name="txtChar">
  </BODY>
</HTML>



All times are GMT +5.5. The time now is 18:35.