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-   -   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

Miles Tegg 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.

Miles Tegg 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>


Saket 21Jul2009 12:01

Re: Allow Only Numbers in a Textbox
 
Ohh thats great, you have used ascii, but what about without using ascii, can we achieve it ?

WebspoonUK 7Apr2010 04:44

Re: Allow Only Numbers in a Textbox
 
In order to detect the shift key, you can add a hidden input box and set its value to 1 whenever the shift key is pressed from within your js function. Then simply check the value of the hidden input box and disallow/allow as necessary (You will need two events to do this - keydown and keypress).

Manojbijnori 7Apr2010 15:44

Re: Allow Only Numbers in a Textbox
 
This is an example for allowing only number in textbox I think this will help you
Code:

import java.awt.Container;
import java.awt.Graphics;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.PlainDocument;

public class ValidationTestFrame extends JFrame implements DocumentListener {
  JLabel label = new JLabel("I only accept numbers");
  private IntTextField intFiled;

  public ValidationTestFrame() {
    setTitle("ValidationTest");
    setSize(300, 200);
    addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e) {
        System.exit(0);
      }
    });

    Container contentPane = getContentPane();

    JPanel p = new JPanel();
    intFiled = new IntTextField(12, 3);
    p.add(intFiled);
    intFiled.getDocument().addDocumentListener(this);

    contentPane.add(p, "South");
    contentPane.add(label, "Center");
  }

  public void insertUpdate(DocumentEvent e) {
    setLabel();
  }

  public void removeUpdate(DocumentEvent e) {
    setLabel();
  }

  public void changedUpdate(DocumentEvent e) {
  }

  public void setLabel() {
    if (intFiled.isValid() ) {
      int value = intFiled.getValue();
      label.setText(Integer.toString(value));
    }
  }

  public static void main(String[] args) {
    JFrame frame = new ValidationTestFrame();
    frame.show();
  }

}

class IntTextField extends JTextField {
  public IntTextField(int defval, int size) {
    super("" + defval, size);
  }

  protected Document createDefaultModel() {
    return new IntTextDocument();
  }

  public boolean isValid() {
    try {
      Integer.parseInt(getText());
      return true;
    } catch (NumberFormatException e) {
      return false;
    }
  }

  public int getValue() {
    try {
      return Integer.parseInt(getText());
    } catch (NumberFormatException e) {
      return 0;
    }
  }
  class IntTextDocument extends PlainDocument {
    public void insertString(int offs, String str, AttributeSet a)
        throws BadLocationException {
      if (str == null)
        return;
      String oldString = getText(0, getLength());
      String newString = oldString.substring(0, offs) + str
          + oldString.substring(offs);
      try {
        Integer.parseInt(newString + "0");
        super.insertString(offs, str, a);
      } catch (NumberFormatException e) {
      }
    }
  }

}


sharma.kapil28 22Jul2011 15:53

Re: Allow Only Numbers in a Textbox
 
use isNaN
for more detail with example
visit
urfusion.blogspot

FaysalAhmed 4Oct2011 10:15

Re: Allow Only Numbers in a Textbox
 
hi,
i used the code above and find the following error, event is not defined

how ever i used the following code and it worked fine,

Code:

function onlyNumbers(evt)
            {
              /* if (!evt) {
                    evt = window.event;
                } */

                var e = window.event || evt; // for trans-browser compatibility
                var charCode = e.which || e.keyCode;

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

                return true;

            }

any idea about this issue?

tinytomhanks 26Apr2012 02:52

Re: Allow Only Numbers in a Textbox
 
I am just starting java script, I'll use this code soon. thank you for sharing.

newindiasolutions 28Apr2012 10:54

Re: Allow Only Numbers in a Textbox
 
Web development is beautiful field and in search engine optimization it is more important. Because there is main work on website.

edwardallene 4May2012 07:31

Re: Allow Only Numbers in a Textbox
 
Is it possible to combine the characters as well as the numbers? What problem could fix your codes? Calculator? Digit Problem Solving? Anyway, this would add information to my HTML note. Thanks for the information.

c_user 19Jan2013 11:19

Re: Allow Only Numbers in a Textbox
 
The HTML tag goes like this:

Code:

<form action="#.html" onsubmit=" return validate();" name="myform" method="post" style="border:thin;" >
                <table align="center" bgcolor="#CCCCCC"; cellpadding="2px" style="text-align:left">
    <tr>       
                    <th>Contact No.</th><td><input type="text" id="cont" name="cont" /><font size="+0" color="#FF0000">*</font></td>
    </tr>
</table>
</form>

The javascript goes :
Code:

function validate()
{
if( Uize.isNaN(document.getElementById("cont").value))
        {
                alert("Invalid Number.");
                return false;
        }
}

>>>Happy coding <<<


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