In main list if suppose there are 3 topics if i click one topic it should expand list in that i should select one sub topic and if click the 2nd topic in the main list it should expand in that i should select one sub topic and if i click 3rd topic in the main list it should expand in that i should one sub topic.... By selecting like this three topics and then if give submit after that it should the related contents based on the three topics...can help me for this concept can you give example coding for this...