Click here to Skip to main content
15,667,847 members
Articles / Web Development / HTML
Posted 18 Apr 2011


26 bookmarked

Text box to accept only number

Rate me:
Please Sign up or sign in to vote.
4.13/5 (21 votes)
23 Apr 2011CPOL
Text box to accept only number
   <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;
      <INPUT id="txtChar" onkeypress="return isNumberKey(event)" type="text" name="txtChar">

Just paste the Script Section in the Head section and in on key press call the function.
For C#, just paste the following code:

function allownumbers(e) {
        var key = window.event ? e.keyCode : e.which;
        var keychar = String.fromCharCode(key);
        var reg = new RegExp("[0-9.]")
        if (key == 8) {
            keychar = String.fromCharCode(key);

And in PageLoad:
txtNum.Attributes.Add("onkeypress", "javascript:return allownumbers(event);");


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Written By
Software Developer India
India India
Total DotNet/Programming Solution

I am Prasanta Banerjee. I am an Asp.Net Developer. My site:
If any body wants to prepare for interview is the good site.

Comments and Discussions

QuestionGood Solution Pin
Alireza_136220-Mar-13 22:24
Alireza_136220-Mar-13 22:24 
GeneralMy vote of 2 Pin
niubay11-Sep-12 3:31
niubay11-Sep-12 3:31 
GeneralRe: by small digits I mean something like: 1.2345, 6.78 etc I ... Pin
Huisheng Chen24-Apr-11 12:14
Huisheng Chen24-Apr-11 12:14 
GeneralRe: Agreed. Something like this regular expression /^-?[0-9]+(\.... Pin
danlobo29-Dec-11 23:32
danlobo29-Dec-11 23:32 
GeneralRe: Negative values you just have to program to allow the minus ... Pin
Ed Nutting24-Apr-11 3:08
Ed Nutting24-Apr-11 3:08 
GeneralRe: The keyboard remapping just assigns different characters to ... Pin
AspDotNetDev24-Apr-11 0:44
protectorAspDotNetDev24-Apr-11 0:44 
GeneralRe: For starters you can remap your keyboard but also, the world... Pin
Ed Nutting23-Apr-11 22:57
Ed Nutting23-Apr-11 22:57 
For starters you can remap your keyboard but also, the world isn't just ASCII you know, there's UTF-8 etc. Also, how about my sister's Russian keyboard that is completely different, I would doubt that that maps exactly the same. Perhaps the numbers might be the same but as a general rule, use chars, it's safer.
GeneralReason for my vote of 5 exclent Pin
lovepreet_shota18-Jun-11 17:15
lovepreet_shota18-Jun-11 17:15 
GeneralThis is all well and good unless of course my keyboards numb... Pin
Ed Nutting23-Apr-11 2:40
Ed Nutting23-Apr-11 2:40 
GeneralRe: What do you mean? How would your keyboard number keys use di... Pin
AspDotNetDev23-Apr-11 18:51
protectorAspDotNetDev23-Apr-11 18:51 
GeneralRe: what if small digits or negative values? I think using regex... Pin
Huisheng Chen24-Apr-11 3:05
Huisheng Chen24-Apr-11 3:05 
GeneralExplanation needed Pin
Indivara18-Apr-11 12:05
professionalIndivara18-Apr-11 12:05 
GeneralRe: Explanation needed Pin
Prasad_Kulkarni27-Dec-11 18:52
Prasad_Kulkarni27-Dec-11 18:52 

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Praise Praise    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.