Electronic devices having touch screens are increasingly favored by consumers, for example, devices such as a smartphone, a tablet computer, and a personal digital assistant (PDA). Usually a user performs slide and touch operations on a touch screen to perform zooming processing on a browsed page. For multi-touch of a smartphone, a relative sliding distance of two fingers on a touch screen is sensed in order to control zooming out or zooming in of a page.
In some other approaches, although various page display control technologies are available, two fingers always need to be used to operate a touch screen to realize zooming of a page. Usually, one hand holds an electronic device, and the other hand performs zooming control. It is difficult to hold an electronic device and at the same time perform a zooming operation using a single hand.