Textareas are used to show codes. One good example could be this one:
To get a textarea, copy the code below (remove the *):
<*textarea>CODE HERE<*/textarea>
If you'd like to have a textarea which content is all selected with a click, use the code below. Example:
<*textarea readonly onClick="this.focus();this.select()">CODE HERE<*/textarea>
To resize a textarea, you need to use attributes, cols and rows, that stand for columns and rows. Cols would be the textarea width, while rows would be the height.
<*textarea cols="NUMBER" rows="NUMBER">CODE HERE<*/textarea>