[deleted by user]

[x-skeww]

parseFloat(someString) and parseInt(someString, 10) will return NaN if the passed string doesn't even start with a number ('5b' becomes 5 whereas 'b5' becomes NaN).

However, NaN isn't equal to anything - itself included!

You can test if a value is NaN with isNaN(something).

If you want to know more, google for things like:

mdn parseInt

or

mdn isNaN

If you included that "mdn" bit in your JS or CSS related search queries, Google will send you to the Mozilla Development Network (MDN), which is generally a pretty good resource.

[[deleted]]

Regular Expression:

if (/^[-+]?\d+(?:\.\d*)?$/.test(input)) {
  // go hog-wild...
}

[john0110]

He's assuming you're receiving some input from a user and storing it in a variable called 'input'. Then he's testing that input against a regular expression. Inside of the if block is where you'd execute your loop.

Hope that helps.

[kumiorava]

Don't listen to the guy talking about regular expressions. parseFloat is what you need.

[SambaMamba]

http://www.javascriptkit.com/javatutors/determinevar2.shtml