how to over come from this problem

 i have two buttons and one textbox is in my web page.i want to retrive data from database afer clicking buttons.to the text box.
i have two fields in my database table.if i click on first button the textbox contains something..if clicking on second button the textbox contains something .
now my problem is .iam clicking on second button.first button data is not showed in textbox.

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