How to reload the page in asp?

I have 2 dropdown list boxes in my asp page where I need to select category and sub-category.

Sub-category dropdown list will be populated based on the category dropdown list box selection.

The problem is the sub-category list box is not loading accordingly when i select an item in category list box.

So I am going to previous page and click on the button to get the current page(where cateory &a开发者_开发知识库mp; sub category list boxes are located) and selecting the sub category details(now sub category list box got loaded).

Is there any way to stay on the current page and get the sub category list box loaded for selection at first time itself. Please any one help..

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Set AutoPostBack=true and handle ChangeItem event at category dropDown.

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@Kanchana: This should help get you started -- http://www.satya-weblog.com/2009/08/jquery-ajax-example-of-select-values.html