How to validate digits (including floats) in javascript

Question

Currently i'm using this reg exp:

var valid = (value.match(/^\d+$/)); 

But for digits like '0.40', or '2.43' this doesn't work. How can I change that reg exp above to match floats as well?

Answer 1

You don't need regex for this! isNaN will cast thine value to Number:

var valid = !isNaN(value); 

Eg:

!isNaN('0'); // true !isNaN('34.56'); // true !isNaN('.34'); // true !isNaN('-34'); // true !isNaN('foo'); // false !isNaN('08'); // true 

Reluctant Edit (thanks CMS):

Blasted type coercion, !isNaN(''), !isNaN(' '), !isNaN('\n\t'), etc are all true!

Whitespace test + isNaN FTW:

var valid = !/^\s*$/.test(value) && !isNaN(value); 

Yuck.