Javascript Regexp validation not quite working

Question

I am trying to use RegExp validation for a number that can have up to 5 numbers followed up one option decimal place. Like 48293 or 23.4 are good. 99.99 or 453543 are not. I wrote the following function:

function validateLoad(load_value) {
 var matchValue = new RegExp('[0-9]{1,5}(\.[0-9]{1})?')
 return matchValue.test(load_value)
}

However, this seems to return true for all numerical values, can anyone tell me how to fix this?

up to means from 0, then you should change to [0-9]{0,5}

1252748
– 1252748

2013-11-20 20:55:47 +00:00
Commented Nov 20, 2013 at 20:55 — 1252748
– 1252748, Commented Nov 20, 2013 at 20:55

Tim Pietzcker · Accepted Answer · 2013-11-20 20:41:39Z

3

You need to use anchors to make sure the entire string (and not just a substring) is matched by the regex. Also, don't forget to double the backslashes if you construct the regex from a string (and drop the {1}, it's a no-op):

var matchValue = new RegExp('^[0-9]{1,5}(\\.[0-9])?$');

answered Nov 20, 2013 at 20:41

Tim Pietzcker

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1 Comment

Tim Pietzcker Over a year ago

@thomas: No operation - a command without any effect. Every token is matched exactly once by definition, unless stated otherwise. So x and x{1} are identical.

score 0 · Accepted Answer · 2013-11-20 21:13:27Z

0

Using literal notation would avoid to escape backslashes :

function validateLoad(load_value) {
    return /^\d{1,5}(\.\d)?$/.test(load_value)
}

edited Nov 20, 2013 at 21:13

answered Nov 20, 2013 at 20:57

user1636522

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