HTML5 input type=number value is empty in Webkit if has spaces or non-numeric characters?

HTML5 input type=number value is empty in Webkit if has spaces or
non-numeric characters?

This is strange behavior to me but on Webkit browsers (Chrome/Safari, not
Firefox) if I include a space in a string of numbers in an <input
type=number> then the value of that input is empty.
See this JSFiddle: http://jsfiddle.net/timrpeterson/CZZEX/5/
Here's the code:
<input id='withOutspace' type='number' value='123'>
<input id='with_space' type='number' value='123 123'>
<button>click</button>
$('button').click(function(){
alert("withOut:"+$('#withOutspace').val()+" ||||
with:"+$('#with_space').val());
});
If you go to this JSFiddle, you'll notice that the with_space input is
empty. But if you put it in it a number that has a space or any
non-numeric characters, the alert will say that input is empty.
Obviously, this is a disaster for form validation with credit card
numbers, etc. so does anyone have a hack for this?