Filtering “whitespace-only” strings in JavaScript

Question

I have a textbox collecting user input in my JS code. I would like to filter junk input, like strings that contain whitespaces only.

In C#, I would use the following

Answer 1

Use a regular expression:

if (inputString.match(/^\s*$/)) { alert("not ok"); }

or even easier:

if (inputString.match(/\S/)) { alert("ok"); }

The \S means 'any non white space character'.