Regular expression JavaScript

Question

I have modal pop up for adding data, I have to validate textbox using JavaScript regular expression for numeric values only. I want to enter only numbers in text box, so tell me what is proper numeric regular expression for that?

Is is integers only or do you want to have stuff like floats, rationals, scientific notation or complex? — Jakub Hampl
– Jakub Hampl, Commented Mar 24, 2011 at 13:57
And, actually, I messed up the pattern. It should be ^\d+(?:\.\d+)?$ (The final * would allow 1.2.3.4, which wouldn't be a valid number.) — Brad Christie
– Brad Christie, Commented Mar 24, 2011 at 14:15
Jakob's question is worth repeating: What, exactly, is a "numeric value"? See: What’s a Number? — ridgerunner
– ridgerunner, Commented Mar 24, 2011 at 17:24
Even better just put <input type="number">, but otherwise /^[0-9]$/ — Inspiraller
– Inspiraller, Commented Sep 10, 2020 at 14:32

Toto · Accepted Answer · 2011-03-24 15:04:19Z

2

Why not using isNaN ? This function tests if its argument is not a number so :

if (isNaN(myValue)) {
   alert(myValue + ' is not a number');
} else {
   alert(myValue + ' is a number');
}

answered Mar 24, 2011 at 15:04

Toto

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1 Comment

HBP Over a year ago

isNAN will report a number for '0xabcd' since it is a valid hexadecimal number.

Martin Jespersen · Accepted Answer · 2011-03-24 13:56:01Z

1

You can do it as simple as:

function hasOnlyNumbers(str) {
 return /^\d+$/.test(str);
}

Working example: http://jsfiddle.net/wML3a/1/

answered Mar 24, 2011 at 13:56

Martin Jespersen

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Comments

Jakub Hampl · Accepted Answer · 2011-03-24 13:56:50Z

0

^\d+$ of course if you want to specify that it has to be at least 4 digits long and not more than 20 digits the pattern would then be => ^\d{4,20}$

edited Mar 24, 2011 at 13:56

Jakub Hampl

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answered Mar 24, 2011 at 13:55

pythonian29033

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