Regex for empty string or white space

If you are looking for empty string in addition to whitespace you meed to use * rather than +

var regex = /^\s*$/ ;
                ^

The \ (backslash) in the .match call is not properly escaped. It would be easier to use a regex literal though. Either will work:

var regex = "^\\s+$";
var regex = /^\s+$/;

Also note that + will require at least one space. You may want to use *.