Clearing all options from a select

OUCH! I wrote this post to only later learn that doing anything like this:

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

is just dumb. A million times better solution is:

document.getElementById(this.listName).length = 0;

Don't you hate when an answer is blindingly obvious? I just figured that length would be read only. Oh well.