哪位大佬帮忙解释一下首页模板上滑自动加载数据的JavaScript代码？？

/*!*http://bbs.design信息瀑布流内容自动加载js代码*/varIASCallbacks=function(){returnthis.list=[],this.fireStack=[],this.isFiring=!1,this.isDisabled=!1,this.fire=function(a){varb=a[0],c=a[1],d=a[2];this.isFiring=!0;for(vare=0,f=this.list.length;f>e;e++)if(void0!=this.list[e]&&!1===this.list[e].fn.apply(b,d)){c.reject();break}this.isFiring=!1,c.resolve(),this.fireStack.length&&this.fire(this.fireStack.shift())},this.inList=function(a,b){b=b||0;for(varc=b,d=this.list.length;d>c;c++)if(this.list[c].fn===a||a.guid&&this.list[c].fn.guid&&a.guid===this.list[c].fn.guid)returnc;return-1},this};IASCallbacks.prototype={add:function(a,b){varc={fn:a,priority:b};b=b||0;for(vard=0,e=this.list.length;e>d;d++)if(b>this.list[d].priority)returnthis.list.splice(d,0,c),this;returnthis.list.push(c),this},remove:function(a){for(varb=0;(b=this.inList(a,b))>-1;)this.list.splice(b,1);returnthis},has:function(a){returnthis.inList(a)>-1},fireWith:function(a,b){varc=jQuery.Deferred();returnthis.isDisabled?c.reject():(b=b||[],b=[a,c,b.slice?b.slice():b],this.isFiring?this.fireStack.push(b):this.fire(b),c)},disable:function(){this.isDisabled=!0},enable:function(){this.isDisabled=!1}},function(a){"usestrict";varb=-1,c=function(c,d){returnthis.itemsContainerSelector=d.container,this.itemSelector=d.item,this.nextSelector=d.next,this.paginationSelector=d.pagination,this.$scrollContainer=c,this.$container=window===c.get(0)?a(document):c,this.defaultDelay=d.delay,this.negativeMargin=d.negativeMargin,this.nextUrl=null,this.isBound=!1,this.isPaused=!1,this.isInitialized=!1,this.listeners={next:newIASCallbacks,load:newIASCallbacks,loaded:newIASCallbacks,render:newIASCallbacks,rendered:newIASCallbacks,scroll:newIASCallbacks,noneLeft:newIASCallbacks,ready:newIASCallbacks},this.extensions=[],this.scrollHandler=function(){if(this.isBound&&!this.isPaused){vara=this.getCurrentScrollOffset(this.$scrollContainer),c=this.getScrollThreshold();b!=c&&(this.fire("scroll",[a,c]),a>=c&&this.next())}},this.getItemsContainer=function(){returna(this.itemsContainerSelector)},this.getLastItem=function(){returna(this.itemSelector,this.getItemsContainer().get(0)).last()},this.getFirstItem=function(){returna(this.itemSelector,this.getItemsContainer().get(0)).first()},this.getScrollThreshold=function(a){varc;returna=a||this.negativeMargin,a=a>=0?-1*a:a,c=this.getLastItem(),0===c.length?b:c.offset().top+c.height()+a},this.getCurrentScrollOffset=function(a){varb=0,c=a.height();returnb=window===a.get(0)?a.scrollTop():a.offset().top,(-1!=navigator.platform.indexOf("iPhone")||-1!=navigator.platform.indexOf("iPod"))&&(c+=80),b+c},this.getNextUrl=function(b){returnb=b||this.$container,a(this.nextSelector,b).last().attr("href")},this.load=function(b,c,d){vare,f,g=this,h=[],i=+newDate;d=d||this.defaultDelay;varj={url:b};returng.fire("load",[j]),a.get(j.url,null,a.proxy(function(b){e=a(this.itemsContainerSelector,b).eq(0),0===e.length&&(e=a(b).filter(this.itemsContainerSelector).eq(0)),e&&e.find(this.itemSelector).each(function(){h.push(this)}),g.fire("loaded",[b,h]),c&&(f=+newDate-i,d>f?setTimeout(function(){c.call(g,b,h)},d-f):c.call(g,b,h))},g),"html")},this.render=function(b,c){vard=this,e=this.getLastItem(),f=0,g=this.fire("render",[b]);g.done(function(){a(b).hide(),e.after(b),a(b).fadeIn(400,function(){++f<b.length||(d.fire("rendered",[b]),c&&c())})})},this.hidePagination=function(){this.paginationSelector&&a(this.paginationSelector,this.$container).hide()},this.restorePagination=function(){this.paginationSelector&&a(this.paginationSelector,this.$container).show()},this.throttle=function(b,c){vard,e,f=0;returnd=function(){functiona(){f=+newDate,b.apply(d,g)}vard=this,g=arguments,h=+newDate-f;e?clearTimeout(e):a(),h>c?a():e=setTimeout(a,c)},a.guid&&(d.guid=b.guid=b.guid||a.guid++),d},this.fire=function(a,b){returnthis.listeners[a].fireWith(this,b)},this.pause=function(){this.isPaused=!0},this.resume=function(){this.isPaused=!1},this};c.prototype.initialize=function(){if(this.isInitialized)return!1;vara=!!("onscroll"inthis.$scrollContainer.get(0)),b=this.getCurrentScrollOffset(this.$scrollContainer),c=this.getScrollThreshold();returna?(this.hidePagination(),this.bind(),this.fire("ready"),this.nextUrl=this.getNextUrl(),b>=c?(this.next(),this.one("rendered",function(){this.isInitialized=!0})):this.isInitialized=!0,this):!1},c.prototype.reinitialize=function(){this.isInitialized=!1,this.unbind(),this.initialize()},c.prototype.bind=function(){if(!this.isBound){this.$scrollContainer.on("scroll",a.proxy(this.throttle(this.scrollHandler,150),this));for(varb=0,c=this.extensions.length;c>b;b++)this.extensions[b].bind(this);this.isBound=!0,this.resume()}},c.prototype.unbind=function(){if(this.isBound){this.$scrollContainer.off("scroll",this.scrollHandler);for(vara=0,b=this.extensions.length;b>a;a++)"undefined"!=typeofthis.extensions[a].unbind&&this.extensions[a].unbind(this);this.isBound=!1}},c.prototype.destroy=function(){this.unbind(),this.$scrollContainer.data("ias",null)},c.prototype.on=functio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nction(){for(vard=1,g=b.pagebreaks.length;g>d;d++)b.pagebreaks[d][0]=b.pagebreaks[d][0]+f.offset().top;varh=b.getCurrentPageNum(e)+1;c.fire("pageChange",[h,e,a]),b.lastPageNum=h,b.enabled=!0})},this};IASPagingExtension.prototype.initialize=function(a){this.ias=a,jQuery.extend(a.listeners,this.listeners)},IASPagingExtension.prototype.bind=function(a){try{a.on("prev",jQuery.proxy(this.onPrev,this),this.priority)}catch(b){}a.on("next",jQuery.proxy(this.onNext,this),this.priority),a.on("scroll",jQuery.proxy(this.onScroll,this),this.priority)},IASPagingExtension.prototype.unbind=function(a){try{a.off("prev",this.onPrev)}catch(b){}a.off("next",this.onNext),a.off("scroll",this.onScroll)},IASPagingExtension.prototype.getCurrentPageNum=function(a){for(varb=this.pagebreaks.length-1;b>0;b--)if(a>this.pagebreaks[b][0])returnb+1;return1},IASPagingExtension.prototype.getCurrentPagebreak=function(a){for(varb=this.pagebreaks.length-1;b>=0;b--)if(a>this.pagebreaks[b][0])returnthis.pagebreaks[b];returnnull},IASPagingExtension.prototype.priority=500;varIASSpinnerExtension=function(a){returna=jQuery.extend({},this.defaults,a),this.ias=null,this.uid=(newDate).getTime(),this.src=a.src,this.html=a.html.replace("{src}",this.src),this.showSpinner=function(){vara=this.getSpinner()||this.createSpinner(),b=this.ias.getLastItem();b.after(a),a.fadeIn()},this.showSpinnerBefore=function(){vara=this.getSpinner()||this.createSpinner(),b=this.ias.getFirstItem();b.before(a),a.fadeIn()},this.removeSpinner=function(){this.hasSpinner()&&this.getSpinner().remove()},this.getSpinner=function(){vara=jQuery("#ias_spinner_"+this.uid);returna.length>0?a:!1},this.hasSpinner=function(){vara=jQuery("#ias_spinner_"+this.uid);returna.length>0},this.createSpinner=function(){vara=jQuery(this.html).attr("id","ias_spinner_"+this.uid);returna.hide(),a},this};IASSpinnerExtension.prototype.bind=function(a){this.ias=a,a.on("next",jQuery.proxy(this.showSpinner,this)),a.on("render",jQuery.proxy(this.removeSpinner,this));try{a.on("prev",jQuery.proxy(this.showSpinnerBefore,this))}catch(b){}},IASSpinnerExtension.prototype.unbind=function(a){a.off("next",this.showSpinner),a.off("render",this.removeSpinner);try{a.off("prev",this.showSpinnerBefore)}catch(b){}},IASSpinnerExtension.prototype.defaults={html:'<divclass="zhanzhuai-loading"><divclass="load-iconload-icon-1"></div><divclass="load-iconload-icon-2"></div><divclass="load-iconload-icon-3"></div><span>玩命加载中...</span></div>'};varIASTriggerExtension=function(a){returna=jQuery.extend({},this.defaults,a),this.ias=null,this.html=a.html.replace("{text}",a.text),this.htmlPrev=a.htmlPrev.replace("{text}",a.textPrev),this.enabled=!0,this.count=0,this.offset=a.offset,this.$triggerNext=null,this.$triggerPrev=null,this.showTriggerNext=function(){if(!this.enabled)return!0;if(!1===this.offset||++this.count<this.offset)return!0;vara=this.$triggerNext||(this.$triggerNext=this.createTrigger(this.next,this.html)),b=this.ias.getLastItem();returnb.after(a),a.fadeIn(),!1},this.showTriggerPrev=function(){if(!this.enabled)return!0;vara=this.$triggerPrev||(this.$triggerPrev=this.createTrigger(this.prev,this.htmlPrev)),b=this.ias.getFirstItem();returnb.before(a),a.fadeIn(),!1},this.onRendered=function(){this.enabled=!0},this.createTrigger=function(a,b){varc,d=(newDate).getTime();returnb=b||this.html,c=jQuery(b).attr("id","ias_trigger_"+d),c.hide(),c.on("click",jQuery.proxy(a,this)),c},this};IASTriggerExtension.prototype.bind=function(a){this.ias=a,a.on("next",jQuery.proxy(this.showTriggerNext,this),this.priority),a.on("rendered",jQuery.proxy(this.onRendered,this),this.priority);try{a.on("prev",jQuery.proxy(this.showTriggerPrev,this),this.priority)}catch(b){}},IASTriggerExtension.prototype.unbind=function(a){a.off("next",this.showTriggerNext),a.off("rendered",this.onRendered);try{a.off("prev",this.showTriggerPrev)}catch(b){}},IASTriggerExtension.prototype.next=function(){this.enabled=!1,this.ias.pause(),this.$triggerNext&&(this.$triggerNext.remove(),this.$triggerNext=null),this.ias.next()},IASTriggerExtension.prototype.prev=function(){this.enabled=!1,this.ias.pause(),this.$triggerPrev&&(this.$triggerPrev.remove(),this.$triggerPrev=null),this.ias.prev()},IASTriggerExtension.prototype.defaults={text:"加载更多",html:'<divclass="zhanzhuai-ajax-more"style="text-align:center;cursor:pointer;"><a>{text}</a></div>',textPrev:"Loadpreviousitems",htmlPrev:'<divclass="ias-triggerias-trigger-prev"style="text-align:center;cursor:pointer;"><a>{text}</a></div>',offset:0},IASTriggerExtension.prototype.priority=1e3;

上面代码是自别的网站上扒下来的，研究用的。功能仿知乎首页信息瀑布流功能。