jquery 回到顶部插件
//** jQuery Scroll to Top Control script- (c) Dynamic Drive DHTML code library: http://www.dynamicdrive.com.//** Available/ usage terms at http://www.dynamicdrive.com (March 30th, 09')//** v1.1 (April 7th, 09')://** 1) Adds ability to scroll to an absolute position (from top of page) or specific element on the page instead.//** 2) Fixes scroll animation not working in Opera. var scrolltotop={//startline: Integer. Number of pixels from top of doc scrollbar is scrolled before showing control//scrollto: Keyword (Integer, or "Scroll_to_Element_ID"). How far to scroll document up when control is clicked on (0=top).setting: {startline:1, scrollto: 0, scrollduration:1000, fadeduration:[500, 100]},controlHTML: '回到顶部', //HTML for control, which is auto wrapped in DIV w/ ID="topcontrol"controlattrs: {offsetx:5, offsety:5}, //offset of control relative to right/ bottom of window corneranchorkeyword: '#top', //Enter href value of HTML anchors on the page that should also act as "Scroll Up" linksstate: {isvisible:false, shouldvisible:false},scrollup:function(){if (!this.cssfixedsupport) //if control is positioned using JavaScriptthis.$control.css({opacity:0}) //hide control immediately after clicking itvar dest=isNaN(this.setting.scrollto)? this.setting.scrollto : parseInt(this.setting.scrollto)if (typeof dest=="string" && jQuery('#'+dest).length==1) //check element set by string existsdest=jQuery('#'+dest).offset().topelsedest=0this.$body.animate({scrollTop: dest}, this.setting.scrollduration);},keepfixed:function(){var $window=jQuery(window)var controlx=$window.scrollLeft() + $window.width() - this.$control.width() - this.controlattrs.offsetxvar controly=$window.scrollTop() + $window.height() - this.$control.height() - this.controlattrs.offsetythis.$control.css({left:controlx+'px', top:controly+'px'})},togglecontrol:function(){var scrolltop=jQuery(window).scrollTop()if (!this.cssfixedsupport)this.keepfixed()this.state.shouldvisible=(scrolltop>=this.setting.startline)? true : falseif (this.state.shouldvisible && !this.state.isvisible){this.$control.stop().animate({opacity:1}, this.setting.fadeduration[0])this.state.isvisible=true}else if (this.state.shouldvisible==false && this.state.isvisible){this.$control.stop().animate({opacity:0}, this.setting.fadeduration[1])this.state.isvisible=false}},init:function(){jQuery(document).ready(function($){var mainobj=scrolltotopvar iebrws=document.allmainobj.cssfixedsupport=!iebrws || iebrws && document.compatMode=="CSS1Compat" && window.XMLHttpRequest //not IE or IE7+ browsers in standards modemainobj.$body=(window.opera)? (document.compatMode=="CSS1Compat"? $('html') : $('body')) : $('html,body')mainobj.$control=$('<div id="topcontrol">'+mainobj.controlHTML+'</div>').css({position:mainobj.cssfixedsupport? 'fixed' : 'absolute', bottom:mainobj.controlattrs.offsety, right:mainobj.controlattrs.offsetx, opacity:0, cursor:'pointer'}).attr({title:'Scroll Back to Top'}).click(function(){mainobj.scrollup(); return false}).appendTo('body')if (document.all && !window.XMLHttpRequest && mainobj.$control.text()!='') //loose check for IE6 and below, plus whether control contains any textmainobj.$control.css({width:mainobj.$control.width()}) //IE6- seems to require an explicit width on a DIV containing textmainobj.togglecontrol()$('a[href="' + mainobj.anchorkeyword +'"]').click(function(){mainobj.scrollup()return false})$(window).bind('scroll resize', function(e){mainobj.togglecontrol()})})}}scrolltotop.init()?