pic1= new Image(160,42); 
pic1.src="http://www.plumbfit.com/seo_page_button_over.jpg";

function bi(dob) {
document.getElementById(dob).style.backgroundImage='url(http://www.plumbfit.com/seo_page_button_over.jpg)';
lob = dob.replace(/b/, "l")
document.getElementById(lob).style.color='#0000CC';
}
function bo(dob) {
document.getElementById(dob).style.backgroundImage='url(http://www.plumbfit.com/seo_page_button.jpg)';
lob = dob.replace(/b/, "l")
document.getElementById(lob).style.color='#006699';
}