JavaScript to check whether textbox contains only integer or numeric/number values

[Dasty]

Hmmm... it's been a while since I've coded, but I'm unfamiliar with this syntax.

Unfortunately, I tried it and it didn't seem to work, whereas the previous (longer) solution did. This one-line code seemed to return a response of "false" even if a single integer was entered. (using IE 7.0.6)

No, his regular expression check is right. It had to by some typo on your code that makes it to act incorrect. Try this:

<SCRIPT language=javascript>
function checkNum(x)
{
  if (!(/^\d+$/.test(x.value)))
  {
    alert("Only Numeric Values Allowed");
    x.focus();
    return false;
  }
  return true;
}
</SCRIPT>
<input type="text" id="t_field" onChange='checkNum(this)'/>

I just put above advice into the code. As far as i know IE does not have any problems with regular expressions at all. But if you want to check something, you have to write clear what exact format of numbers do you want to validate. Do you want to allow negative / positive numbers? Do you want do check decimal numbers?

[Akshay Accent]

Hi all,

I would like to get the Javascript code to check the textbox contains only numeric values or numbers..

I am using asp.net and c#.net..

Please help me..

Regards,
Mathew

For allowing only numeric values to be placed inside a text box using JavaScript, we need to capture the “onKeyDown ” event for the keyboard. This check is done on client side whenever a user enters a value in the textbox using keyboard keys.

Example of such a script is:

TextBoxTest.Att ributes.Add(”on KeyDown”, “if((event.keyC ode >= 48 && event.keyCode <= 57)||(event.key Code >= 96 && event.keyCode <= 105)||(event.ke yCode == 8 ) ||(event.keyCod e == 9) || (event.keyCode == 12) || (event.keyCode == 27) || (event.keyCode == 37) || (event.keyCode == 39) || (event.keyCode == 46) ){return true;}else{retu rn false;}”);

Regards,
Akshay Jain

[acoder]

Akshay, welcome to Bytes and thanks for your contribution.

Unfortunately, the code you've posted is IE-specific and would not work cross-browser. In addition to that, this being the JavaScript forum, it's better to avoid .NET code and provide just the JavaScript.

Thanks.

[deep4ut]

yes you can use isNaN() function of javascript...

[rajeshsundu]

function chk(val)
{
var a=val.parseInt();
if(a == a+1-1)//answer becomes true only if they are numbers
{
alert("its a number");
}
else
{
alert("not a number");
}

[acoder]

Have you tested your code to see if it works? It seems a very convoluted way to check for integers. See https://developer.mozilla.org/en-US/...jects/parseInt

[rajeshsundu]

function chk(val)
    {
    var a=parseInt(val);
    if(a == a+1-1)//answer becomes true only if they are numbers
    {
    alert("its a number");
    }
    else
    {
    alert("not a number");
    }

This works bro :)

[Dormilich]

there is no need for the a+1-1 bit. if a were NaN (the only value parseInt() gives on failure), even then a==a would be false.

[rajeshsundu]

yes you are right @dormilich:)i'm new to programming and just now learning things..