<pre name="code" class="javascript">//回到顶部js
$(function(){
var $btn_top = $('<a id="scrollTopBtn"><img src="css/web/images/scrollTop.png"></a>');
$btn_top.css({
'display':'none',
'width':'40px',
'height':'40px',
'position':'fixed',
'right':'20px',
'bottom':'100px',
'z-index':'999'
});
$("body").append($btn_top);
$("body").on("click","#scrollTopBtn",function(){
$("html,body").animate({scrollTop: 0},"slow");
});
var $btn = $("#scrollTopBtn");
if($(window).scrollTop() > 100){
$btn.fadeIn(600);
}
$(window).scroll(function(){
if($(window).scrollTop() > 100){
$btn.fadeIn(600);
}else{
$btn.fadeOut(600);
}
});
});