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

**gits** · Oct 18 '07, 08:03 PM

hi ...

you may use javascript built in isNaN() method for that ... it returns true in case it is NotaNumber else you get a false ...

kind regards

**mathewgk80** · Oct 18 '07, 08:58 PM

Originally posted by gits

hi ...

you may use javascript built in isNaN() method for that ... it returns true in case it is NotaNumber else you get a false ...

kind regards

Hi Gits,

Can you please give an example for that???

regards,
Mathew

**gits** · Oct 18 '07, 09:06 PM

ok ... lets assume following example:

Code:

<html>
    <head>
    <script type="text/javascript">
        function check_field(id) {
            var field = document.getElementById(id);
                
            if (isNaN(field.value)) {
                alert('not a number');
            }
        }
    </script>
    </head>
    <body>
    <form>
        <input type="text" id="t_field"/>
        <input type="button" value="check" onclick="check_field('t_field');"/>
    </form>
    </body>
</html>

kind regards

**ananth** · Oct 19 '07, 09:04 AM

HI ,
The code above using NAN will not work properly try this.

[CODE=javascript]function checkNum(x)
{

var s_len=x.value.l ength ;
var s_charcode = 0;
for (var s_i=0;s_i<s_len ;s_i++)
{
s_charcode = x.value.charCod eAt(s_i);
if(!((s_charcod e>=48 && s_charcode<=57) ))
{
alert("Only Numeric Values Allowed");
x.value='';
x.focus();
return false;
}
}
return true;
}

<input type="text" id="t_field" onChange='check Num(this)'/>[/CODE]

This will execute on the field exit or tabbing out of the field.

Hope this would be useful.

**gits** · Oct 19 '07, 10:06 AM

Originally posted by ananth

HI ,
The code above using NAN will not work properly try this.

nope ... it is working properly for the requirement. it checks for numeric values and it works! you didn't say why or what is not working properly!

your code should check for only Integers? you simply could use one line for that:

[CODE=javascript]// in case value is an integer test_result will be true
// otherwise it will be false
var test_result = /^\d+$/.test(value);
[/CODE]
kind regards

**mathewgk80** · Nov 8 '07, 07:26 PM

check whether the textbox contains only integer or numeric values

Hi all,

I would like to check whether the textbox contains only nmumberic values by using javascript...

Please help me...

Regards,
Mathew

**iam_clint** · Nov 8 '07, 07:50 PM

I would use something similar to this and just call this function everytime you need to know if its numeric
[CODE=javascript]
<script>
function isNumeric(val) {
var numeric = true;
var chars = "0123456789 .-,+";
var len = val.length;
var char = "";
for (i=0; i<len; i++) { char = val.charAt(i); if (chars.indexOf( char)==-1) { numeric = false; } }
return numeric;
}
</script>
[/CODE]
so I would say if (isNumeric("wha tever value here")) { alert("Its Numeric!!!"); }

**acoder** · Nov 9 '07, 08:15 AM

Or use regular expressions:
[CODE=javascript]function isNumeric(str) {
return /^\d$/.match(str);
}[/CODE]

**iam_clint** · Nov 9 '07, 02:34 PM

Acoders way is better. Never even thought to do that :)

**acoder** · Nov 9 '07, 04:05 PM

Actually, there's a typo (or rather I missed a +):
[CODE=javascript]function isNumeric(str) {
return /^\d+$/.match(str);
}[/CODE]

**acoder** · Nov 9 '07, 04:24 PM

One more thing, this would only match positive integers, i.e. 0+.

If you want to match real numbers, you could try something like

Code:

/^(\+|-)?[1-9]\d*(\.\d*)?$/

**Kid Electric** · Nov 12 '07, 06:46 AM

Originally posted by gits

nope ... it is working properly for the requirement. it checks for numeric values and it works! you didn't say why or what is not working properly!

your code should check for only Integers? you simply could use one line for that:

[CODE=javascript]// in case value is an integer test_result will be true
// otherwise it will be false
var test_result = /^\d+$/.test(value);
[/CODE]
kind regards

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)

**steve waugh** · Nov 12 '07, 07:11 AM

Hi Mathew

Try this code. It Accepts only Numeric, u can modify it according to ur requirement.

Call the function onKeyPress event of textbox.

[CODE=javascript] function allownumber(e)
{

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

}
if (key == 13)
{
key=8;
keychar = String.fromChar Code(key);
}
return reg.test(keycha r);
}[/CODE]

Thx

Originally posted by mathewgk80

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

**gits** · Nov 12 '07, 08:04 AM

Originally posted by Kid Electric

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)

it uses regEx to check the value ... i cannot test it in IE 7 due to having no IE but it should work ... how do you apply the check?

kind regards

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

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

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