On the last Code Camp at South Florida I told the students attending my session the only way for the text changed event of the textbox to get fired is if other controls, like a button, create a postback. I later found out that is not entirely true. That is one way to catch the event, but the textbox control also has an autopostback property. When this property is set to true, the page will do a postback when the text of the textbox is changed and it looses focus to some other control.
I apologize to everyone on the class for providing incorrect information.
As always... Happy Programming!