By calling the nicEditors.allTextareas() function the below example replaces all 3 textareas on the page with nicEditors. NicEditors will match the size of the editor window with the size of the textarea it replaced.

First Textarea

<br /> sdfvds <br> dsfs <h4>Second Textarea</h4> Some Initial Content was in this textarea

Third Textarea

HTML <b>content</b> <i>default</i> in textarea