Keeping users from messing up entry

[Site Owner]

I have this cool textbox which you can test here: http://www.freewebs.com/moreauctions/addtext.html

As you can see it adds a linebreak after each text is added. It is meant to creat a list to be output from a form. But a user can click inside the textarea end mess up the list and enter anyway they want.

How can I make sure that there is always a linebreak between each line of text?

<input size="20" id="inputtext">
<input name="add" value="Add" onclick="document.getElementById('textarea').value+='•'+inputtext.value+'\n\n';" type="button">
<textarea rows="15" id="textarea" name="box" cols="22"></textarea>

I have considered the readonly option but I need users to be able to delete entries.

[mrhoo]

I'd use a group of text input boxes, one for each new list item.