This is a simple project to show how to use the ACE Editor with a textarea.
The Editor itself is housed in a DIV. When the user clicks the Save button, an event takes the code output from ACE and puts it into a textarea. This textarea could be inside of a form element that gets saved when the user clicks to save their data.
The Editor gets its initial code from an AJAX call that pulls a text file and puts the text into the #editor DIV. Optionally, you could just write the code into the #editor DIV on the page.