This example explains how you can trigger events based on user input of a drop down using jQuery.
Here’s the entire page, I have 2 drop downs. On the page load the first drop down is shown, while the second drop down is hidden. Once the user selects any option from the first drop down the change event is triggered and the second option is shown.
In the jQuery code you’ll see that it’s selecting the first drop down and listening for the change function. When it fires it then shows the second dropdown.