This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
That won't only detect a blank (or more precisely empty) String, but also a String containing whitespace only, which is something different. You can use a similar technique to detect an empty String:-CR