It's actually classed as bad practise to have inline onmouseover events nowadays. If they're defined in a script file, it saves one repeating code.
Hi jefals, welcome to SitePoint!
Here is some more info from the SP reference:
I appreciate the help!
you can use
document.getElementById('xx') = x;
yes, I agree, re. keeping it in a separate script file. But I know I will see these types of statements in the htmls, so I am thankful to these forums where I can ask the pros, and get some understanding. I guess the best way to learn is in a classroom where, when you have questions, there's an instructor right there to answer -- but this is a pretty good substitute!.