Javascript checking for float

Question

I've got an app that users input coordinates into.

In the DB and most mapping software they use the decimal notation for lat/lng (eg. 123.1234) rather than the older format: 34N 40' 50.12"

I need to test that a value input into a form is a float, and not a string. But using parseFloat on 34N 40' 50.12" returns 34-- which validates using most tests.

Here's what I'm trying, which is a mashup of a few really clever solutions found here-- but so far I can't get the thing to work properly for all cases. The basic cases I'm testing for are:

• 123.1234 -- valid
• '123.1234' -- valid
• 34N 40' 50.12" -- invalid
• '34N 40' 50.12"' -- invalid
• 123 --valid
• '123' -- valid

Here's a jsfiddle of what I've been trying: http://jsfiddle.net/zfwAj/

• Joseph Marikle: isNaN should work to filter out those ones: jsfiddle.net/QYMRe
• bfavaretto: @JosephMarikle You should add that as an answer, it's the most simple way to test that.
• Bruno: @JosephMarikle Agree. Put it up and I will upvote :)

Answer 1

Seems I should have posted as an answer

isNaN() should work to filter out those ones jsfiddle.net/QYMRe

• julio: @Joseph-- simple, and elegant-- exactly what I was looking for! Thanks.
• Joseph Marikle: @Bruno You're welcome. :) Glad I could help (lol i commented on the wrong spot... it's late)

Answer 2

Try

/^\d+\.?\d*$/.test( str );

Fiddle here

• Ja͢ck: /\D/.test('123.45') // true
• Bruno: @Jack Thank you. came up with a different expression :)

Answer 3

I suggest this one:

/^-?(\d*\.\d+|\d+(\.\d+)?)$/.test(str)

This accepts negative numbers, and float like (.42)

Fiddle test