Jquery ScrollTop

use Jquery-1.4.4.min.js：

Top.js:

$(document).ready(function () {

var show_delay;

var scroll_left = parseInt((document.body.offsetWidth - 960) / 2) + 961;

$(".scroll").click(function () {

document.documentElement.scrollTop = 0;

document.body.scrollTop = 0;

});

$(window).resize(function () {

scroll_left = parseInt((document.body.offsetWidth - 960) / 2) + 961;

$(".scroll").css("left", scroll_left);

}); reshow(scroll_left, show_delay);

});

function reshow(marign_l, show_d) {

$(".scroll").css("left", marign_l);

if ((document.documentElement.scrollTop + document.body.scrollTop) != 0) {

$(".scroll").css("display", "block");

}

else { $(".scroll").css("display", "none"); }

if (show_d) window.clearTimeout(show_d);

show_d = setTimeout("reshow()", 500); }

CSS：

Html：

there is top....