var cache1, cache2, cache3, cache4;

cache1 = new Image();
cache1.src = "images/h1off.gif";
cache2 = new Image();
cache2.src = "images/h1on.gif";
cache3 = new Image();
cache3.src = "images/h2off.gif";
cache4 = new Image();
cache4.src = "images/h2on.gif";
cache5 = new Image();
cache5.src = "images/h3off.gif";
cache6 = new Image();
cache6.src = "images/h3on.gif";
cache7 = new Image();
cache7.src = "images/h4off.gif";
cache8 = new Image();
cache8.src = "images/h4on.gif";
cache9 = new Image();
cache9.src = "images/h5off.gif";
cache10 = new Image();
cache10.src = "images/h5on.gif";
cache11 = new Image();
cache11.src = "images/h6off.gif";
cache12 = new Image();
cache12.src = "images/h6on.gif";

function over(a)
{
    document.getElementById("img" + a).src = "images/" + a + "on.gif";
}
function out(a)
{
    document.getElementById("img" + a).src = "images/" + a + "off.gif";
}