How to display values in a modalpopup on click of a button using Modalpopup

 Hi,
I am trying to implement a seach functionality in my webpage using modalpopup extender.
I have a textbox and a Button in my .aspx webpage.When a  user types some information inside textbox  the results associated with that value should be displayed as a modal popup.(I am using a gridview to display the values).
The result is getting displayed on a modalpopup when ever I click on the search button at the first time...Sorry to say...The modal popup is not getting refreshed when ever  type a new value in my parent page and clicks on the search button again.
Note: .I am using master pages as well.
I have seen some articles about this but consfused ..Please suggest me a clear solution about this.
 (I am working on Asp.net,C#.net 2/3.5 and using master pages too)

Thanks a lot in advance
Pep

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