JavaScript & regex : How do I check if the string is ASCII only?

Question

I know I can validate against string with words ( 0-9 A-Z a-z and underscore ) by applying W in regex like this:

function isValid(str) { return /^\w+$/.test(str); } 

But how do I check whether the string contains ASCII characters only? ( I think I'm close, but what did I miss? )

Reference: https://stackoverflow.com/a/8253200/188331

UPDATE : Standard character set is enough for my case.

Answer 1

All you need to do it test that the characters are in the right character range.

function isASCII(str) {     return /^[\x00-\x7F]*$/.test(str); } 

Or if you want to possibly use the extended ASCII character set:

function isASCII(str, extended) {     return (extended ? /^[\x00-\xFF]*$/ : /^[\x00-\x7F]*$/).test(str); }