Have you ever used textarea in your UI design to get text from user? (Ofcourse you must) :) You must have specified rows and cols attribute to define the height and width of the textarea, or by using CSS. By whatever mean you create your textarea, the width and height of the textarea is fixed. What if you want your user to change the width and height of the textarea or resize the textarea while she is entering the text?
Let us assume that following is your HTML code:
jQuery TextAreaResizer plugin example
Simple textarea + Resizer bar (grippie)