How to create dependent dropdown in drupal 7 content type? I have created a 2 custome content type in drupal 7 one is tourname and another one is location. Once I added a tour name in tour content type like tour1,tour2 and so on. In location content type I added location1, location 2 and so on for each tour name. Now I created third content type name it as details in that I need two drop down one is list of tour I have added and another one is list of location I have inserted. Whenever i changed the tour drop down value, the second drop down value will get automatically updated  based on the tour name.

Thanks in advance.
you need to create a tour and location used Node reference module. And automatically change the drop down  option value of location based on tour option value that you can use ajax .  following url help to u 

Dynamic select list in the form (dependent dropdown)

https://api.drupal.org/api/examples/ajax_example!ajax_example.module/function/ajax_example_dependent_dropdown/7