Touch sensitive display device providing an input interface and controlling method thereof

A touch sensitive display device, comprising:

• a display unit configured to display a graphic user interface;
• a sensor unit configured to sense a contact with the display unit;
• and
• a controller configured to control the display unit and the sensor unit,
• wherein the graphic user interface comprises a first area of a virtual keyboard and a second area of a digital content containing at least one word,
• wherein the controller:
• detects a first contact in the first area;
• displays and moves a word-selecting interface according to the first contact moving from the first area to the second area,
• displays the at least one word overlapped by the word-selecting interface in the digital content as a soft button, respectively,
• detects a second contact from the soft button and
• inputs the word corresponding to the soft button from which the second contact is detected into a text input box.