Handling checkboxes that aren't checked!!!

Hi, I have a page with a Form and a Checkbox. I have a second page which wants to do something depending on if the checkbox is selected or not. If its selected there is no problem. But if I tryand do anything if it isn't selected then it says the variable is 'undefined'. How can I test for it without getting an error if it is not checked?? Or is there a way of ensuring it is either "on" or "off". if ($want_it == TRUE { echo "Selected"; } else { echo "Not Selected";} Will give an undefined eror if the checbox is not selected, but works if it is selected. I have been tearing my hair (what is left) out over the past week and I could really do with some help. Suggestions?? Thanks in advance Kevin