jquery 实现返回顶部功能

今天搞了一个回到顶部的JS JQ功能，废话不多说，有图有真相！

(function($){       

$.fn.survey=function(options){  

var defaults={width:"298",height:"207"};  

var options=$.extend(defaults,options);  

    if($.browser.msie){  

    var ieVersion=parseInt($.browser.version)}  

//建立HTML  

var __feedCreat=function(){  

    var feedHtml=$('<div id="pubFeedBack"></div>');  

    feedHtml.html('<a href="#top" id="backTop"><i></i>\u8fd4\u56de\u9876\u90e8</a><a href="#" id="callSurvey"><i></i>\u610f\u89c1\u53cd\u9988</a>');  

    $("body").append(feedHtml);  

    __ie6Fixed()  

    };  

//绑定事件  

var __initEvent=function(){  

    $(window).resize(function(){  

    var winW=$(this).width();  

    if(winW<=1124){$("#pubFeedBack").hide()}  

    else{$("#pubFeedBack").show()}  

    });  

    $(window).bind("scroll",function(){  

    if($(this).scrollTop()>50){  

    $("#backTop").fadeIn().css({"display":"block"})  

    }  

    else{$("#backTop").fadeOut().css({"display":""})}  

    });  

    $("#backTop").bind("click",function(e){  

    e.preventDefault();                               

    $("html,body").scrollTop(0)});  

};  

//回到顶部  

var __tip=function(type,tipText){  

var surveyTip=$("#D_SurveyTip"),surveyMask=$("#D_SurveyMask");  

if(!surveyTip||!surveyMask){return}  

surveyTip.removeClass("warning success").addClass(type).html(tipText);  

surveyMask.css("display","block");  

surveyTip.css("display","block");  

setTimeout(function(){  

surveyMask.css("display","none");                                                                                                                                                                                                                                                                                       surveyTip.css("display","none")},1000)  

};  

//ie6兼容  

var __ie6Fixed=function(){    

    if(ieVersion!==6){return}  

    var surveyBox=$("#D_SurveyBox");  

    var pubFeedBack=$("#pubFeedBack");  

    if(!surveyBox||!pubFeedBack)  

    {  

        return  

    }  

    $(window).bind("scroll",function(){  

    var h=$(window).height(),st=$(window).scrollTop(),_top=h+st-options.height;                                                                                                                                                         var _top1=h+st-pubFeedBack.height()-15;surveyBox.css("top",_top+"px");  

    pubFeedBack.css("top",_top1+"px")  

    })  

};  

//开始执行  

if(screen.width>=1280)  

{  

    (function(){  

    __feedCreat();                                                                                                                                          __initEvent()                                                                                                                                                       })()  

}  

}  

})(jQuery);  

window.onerror=function(){return false};  

if($.isFunction($(document).survey)){$(document).survey()} 

#backTop i,#callSurvey i{background:url(survey.png) no-repeat;}  

#pubFeedBack{position:fixed;_position:absolute;right:15px;bottom:15px;width:54px;font-size:12px;}  

#backTop,#callSurvey{display:block;width:52px;padding:1px;height:56px;line-height:22px;text-align:center;color:#fff;text-decoration:none;}  

#backTop{display:none;background:#999;}  

#backTop:hover{background:#ccc;zoom:1;text-decoration:none;color:#fff;}  

#backTop i{display:block;width:25px;height:13px;margin:14px auto 8px;background-position:-63px 0;}  

#callSurvey{margin-top:1px;background:#3687d9;}  

#callSurvey:hover{background:#66a4e3;zoom:1;text-decoration:none;color:#fff;}  

#callSurvey i{display:block;width:26px;height:25px;margin:9px auto 0;background-position:0 0;}  

#callSurvey:hover i{background-position:-30px 0;} 

代码很简单，各位直接拿去，放在自己项目中即可，如有bug请给我留言，共同完善

方法二：

主要参数：
scrollName: 'scrollUp', // Element ID
topDistance: '300', // Distance from top before showing element (px)
topSpeed: 300, // Speed back to top (ms)
animation: 'fade', // Fade, slide, none
animationInSpeed: 200, // Animation in speed (ms)
animationOutSpeed: 200, // Animation out speed (ms)
scrollText: 'Scroll to top', // Text for element
activeOverlay: false,
// 帮助定位“回到顶端”按钮出现时滚动到的页面位置。

jquery代码（ScrollUp.js）：

$(function () {
$.scrollUp({
scrollName: 'scrollUp', 
// Element ID
topDistance: '300', 
// Distance from top before showing element (px)
topSpeed: 300, 
// Speed back to top (ms)
animation: 'fade', 
// Fade, slide, none
animationInSpeed: 200, 
// Animation in speed (ms)
animationOutSpeed: 200, 
// Animation out speed (ms)
scrollText: 'Scroll to top', 
// Text for element
activeOverlay: false, 
// set css color to display scrollup active point, e.g '#00ffff'
});
});