Select Boxes - clear all options - except the last one

Update:I was a blithering idiot when I posted this. Read this post. If you're messing with dynamic select boxes here's a good reference. I ran into a problem. Apparently you can't remove the last option (makes sense - how can you have no options?). To make the select appear blank you end up doing something like this:

if (this.selectedDates.length == 0) document.getElementById(this.listName).options[0] = new Option("","");

It just inserts a blank option.