Detect if string is number or has decimal value in javascript

Question

I need users to enter an amount and this may come in different formats like 500 or 500.00. So I need to check if the user has entered a number or a number with two decimal points. SO far I have tried

if(/^\d+$/.test(amount) === false || /[0-9]+(\.[0-9][0-9]?)?/.test(amount) === false){
          //valid
}else{
         //invalid
}

But so far only the one to check if it is a number is working fine.

You want to check that either one of the checks pass, right? Change the falses to true. — JJJ
– JJJ, Commented May 4, 2013 at 17:02

Anirudha · Accepted Answer · 2013-05-04 17:16:55Z

7

I guess you are looking for this

var pattern=/^\d+(\.\d{2})?$/;
if(pattern.test(amount))
{
          //valid number pattern
}
else
{
         //invalid number pattern
}

\d+(\.\d{2})?$ would match 1 to many digits optionally followed by two decimal values..

edited May 4, 2013 at 17:16

answered May 4, 2013 at 17:02

Anirudha

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2 Comments

meze Over a year ago

Save CPU energy: use an assertion instead of capturing: /^\d+(?:\.\d{2})?$/ ;)

Anirudha Over a year ago

@meze nice suggestion..but this is too small footprint for any cpu..:)

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