update panel , textbox lost focus.

[RanjithLogics]

I am using a gridview and a textbox in an update panel. My aim is to search and display the items in the gridview based on the value in textbox. When a string is entered into textbox , it searches the fields that matches the string and binds it to the gridview. It is working perfectly without the full page refresh. The problem is that when I type something fast, it loses the focus, :( and i needed to click the textbox again with mouse in order to continue. If I do it by keeping intervals between keystrokes, it works. Please help me to keep the focus in the textbox always.