I recently started coding. Please help me to write more generic way of writing below code. 

2. function set_selection(elem)
3. {
4. switch(elem.id){
5. case "div_SortCost" :
6. if(elem.id == "div_SortCost")
7. {
8. if(btnSortNumber.elem !=null)
9. {
10. btnSortNumber.disactivateSelection();
11. }
12. if(btnSortCost.elem!=null)
13. {
14. btnSortCost.activateSelection();
15. }
16. if(btnSortHour.elem!=null)
17. {
18. btnSortHour.disactivateSelection();
19. }
20. }
21. break;
23. case "div_SortHour":
24. if(btnSortNumber.elem!=null)
25. {
26. btnSortNumber.disactivateSelection();
27. }
28. if(btnSortCost.elem!=null)
29. {
30. btnSortCost.disactivateSelection();
31. }
32. if(btnSortHour.elem!=null)
33. {
34. btnSortHour.activateSelection();
35. }
36. break;
38. case "div_SortNumber":
39. if(btnSortNumber.elem!=null)
40. {
41. btnSortNumber.activateSelection();
42. }
43. if(btnSortHour.elem!=null)
44. {
45. btnSortHour.disactivateSelection();
46. }
47. if(btnSortCost.elem!=null)
48. {
49. btnSortCost.disactivateSelection();
50. }
51. break;
52. }
53. }

Thanks

Chandu