function mouseOver1()
{
document.b1.src ="homebutton2.gif";
}
function mouseOut1()
{
document.b1.src ="homebutton.gif";
}

function mouseOver2()
{
document.b2.src ="booksbutton2.gif";
}
function mouseOut2()
{
document.b2.src ="booksbutton.gif";
}

function mouseOver3()
{
document.b3.src ="linksbutton2.gif";
}
function mouseOut3()
{
document.b3.src ="linksbutton.gif";
}

function mouseOver4()
{
document.b4.src ="contactbutton2.gif";
}
function mouseOut4()
{
document.b4.src ="contactbutton.gif";
}