var x = 120, y = 0
var xin = true, yin = true
var step = 1
var delay = 10
var obj = $("#ad");
function floatAD() {
    var L = T = 0
    var R = document.documentElement.clientWidth - $("#ad").get(0).offsetWidth;
    var B = document.documentElement.clientHeight - $("#ad").get(0).offsetHeight;
    $("#ad").css("left", x + document.documentElement.scrollLeft);
    $("#ad").css("top", y + document.documentElement.scrollTop);
    x = x + step * (xin ? 1 : -1)
    if (x < L) { xin = true; x = L; }
    if (x > R) { xin = false; x = R }
    y = y + step * (yin ? 1 : -1)
    if (y < T) { yin = true; y = T }
    if (y > B) { yin = false; y = B }
}
var itl = setInterval("floatAD()", delay)
$("#ad").hover(function() { clearInterval(itl); }, function() { itl = setInterval("floatAD()", delay); })