In the web application there's a dropdown with few values (a,b,c), different content is displayed as we select each of them. How to loop through all the values (a,b,c) in the dropdown and run the same script for each value(a,b,c)?
the simplest way to do this with QTP/UFT is to add the values (a,b,c) to a column in your data table.
By default UFT and QTP will automatically run one iteration of the action for each row in the global data table.
The only modification to your script will be changing the WebList().Select from a hard coded value to a parameterised one that references the datatable column.
Look for "Parameterizing Steps and Objects" in the help doc.