i wish to show a hierarchial drop box structure on a web page.For example, there is a wide category called heart disease...when the user selects the category from a drop down list, he should get another listing of sub-categories on a different drop down box on the same page.however, when the user does not know what he's looking for he should be able to choose multiple categories of diseases (from a a wider category ) and then presented the relevant dop down box...for example if he does not know what laminectomy means he should be able to search using multiple selects on a drop box....what is the best way to show this on a web page..radio buttons is one, i think...Any suggestions...?