How to find whether a particular string has unicode characters (esp. Double Byte characters)

Question

To be more precise, I need to know whether (and if possible, how) I can find whether a given string has double byte characters or not. Basically, I need to open a pop-up to

Answer 1

I used mikesamuel answer on this one. However I noticed perhaps because of this form that there should only be one escape slash before the u, e.g. \u and not \\u to make this work correctly.

function containsNonLatinCodepoints(s) {
    return /[^\u0000-\u00ff]/.test(s);
}

Works for me :)