Input overflow problem

[BlindToSound]

I'm making a blog right now, and I have a large input field. It's 535 by 250 pixels..When the texts gets to the other end of the box from the origin, it just makes a scroll bar, and scrolls along with the text. How can I make it stop that, and when it reaches the end, it gets clipped down to the next line? Also, how would I get it to so when I hit enter, it goes to the next line, instead of submitting the form?

Thanks for your help,
Josh

[BlindToSound]

Oh! That worked perfectly, thank you!

<3.