How can I insert a background color to my frameset tag.

Answer 1

Nope, with frames, each document is separate and nothing else is allowed (mostly, the code at the bottom may work in some browsers). You could kind of hack it in like so:

body {
background-image: url('path/to/image.jpg');
background-attachment: fixed;
background-repeat: no-repeat;
}

Answer 2

Yes! Many browsers don't even support frameset. Use iframe.

Answer 3

Don't use html4 frameset/frame: it's outdated... rather learn to use html5 iframe (more flexible, no specific -- ugly -- doctype needed) ^^