How to implement a page that have a drop down list and on clicking any one of the value in the list, then a second drop down list will automatically grab some value from a table in a database and list it down accordingly. I have seen this being implemented on some registration page on the net. For example a drop down list with all the names of the countries. When a country is selected, example US then a second drop down list will load all the names of the states in US. How can I do this using jsp?