(function() {
$backToTopEle = $('').appendTo($("body"))
.click(function() {
$("html, body").animate({ scrollTop: 0 }, 500);
}), $backToTopFun = function() {
var st = $(document).scrollTop(), winh = $(window).height();
(st > 0)? $backToTopEle.show(): $backToTopEle.hide();
//IE6下的定位
if (!window.XMLHttpRequest) {
$backToTopEle.css("top", st + winh - 166);
}
};
$(window).bind("scroll", $backToTopFun);
$(function() { $backToTopFun(); });
})();