How to check if a text is all white space characters in client side?

Question

How to check if a user input text is all white space characters (space, tab, enter etc) in client side?

Answer 1

/^\s+$/.test(userText)

Change the + to * to include the empty string '' as a positive match.

Edit

More often than not though you need to trim whitespace from user-entered text and simply test if it's non-empty:

userText = userText.replace(/^\s+/, '').replace(/\s+$/, '');
if (userText === '') {
    // text was all whitespace
} else {
    // text has real content, now free of leading/trailing whitespace
}