>I have a TEXTAREA in my html page whose width (cols) is initially set such that it is exactly the width of the page. If the page is resized (specifically, the width), can I make the textarea's width adjust such that all information is still displayed and its width is still "100%" of the page? If so, how?

We usually use the table container to determine the width of the textarea. The process consists of DHTMLing the new value of the table width. Then, we can reassign the textarea style width to have this new value.