//Ajax Pagination Script- Author: Dynamic Drive (http://www.dynamicdrive.com)

//** Created Sept 14th, 07'

//** Updated Oct 31st, 07'- Fixed bug when book only contains 1 page

//** Updated Aug 9th 08'- Upgraded to v1.2:

			//1) Adds ability to limit the range of the visible pagination links shown for a book with many pages

			//2) Adds Session only persistence to persist the last page user viewed when navigating away then returning to the webpage containing the script.

			//3) Modified Ajax request function in IE7 to use ActiveXObject object, so script can be tested offline



//** Updated Oct 21st 08'- Upgraded to v1.2.1: Fixed bug with no content showing when there's only one page

//** Updated Dec 1st 08'- v1.2.2: Fixed bug in FF when only one page in book



var ajaxpageclass=new Object()

ajaxpageclass.loadstatustext="Requesting content, please wait..." // HTML to show while requested page is being fetched:

ajaxpageclass.ajaxbustcache=false // Bust cache when fetching pages?

ajaxpageclass.paginatepersist=true //enable persistence of last viewed pagination link (so reloading page doesn't reset page to 1)?

ajaxpageclass.pagerange=4 // Limit page links displayed to a specific number (useful if you have many pages in your book)?

ajaxpageclass.ellipse="..." // Ellipse text (no HTML allowed)



/////////////// No need to edit beyond here /////////////////////////



ajaxpageclass.connect=function(pageurl, divId){

	var page_request = false

	var bustcacheparameter=""

	if (window.XMLHttpRequest && !document.all) // if Mozilla, Safari etc (skip IE7, as object is buggy in that browser)

		page_request = new XMLHttpRequest()

	else if (window.ActiveXObject){ // if IE6 or below

		try {

		page_request = new ActiveXObject("Msxml2.XMLHTTP")

		} 

		catch (e){

			try{

			page_request = new ActiveXObject("Microsoft.XMLHTTP")

			}

			catch (e){}

		}

	}

	else

		return false

	document.getElementById(divId).innerHTML=this.loadstatustext //Display "fetching page message"

	page_request.onreadystatechange=function(){ajaxpageclass.loadpage(page_request, divId)}

	if (this.ajaxbustcache) //if bust caching of external page

		bustcacheparameter=(pageurl.indexOf("?")!=-1)? "&"+new Date().getTime() : "?"+new Date().getTime()

	page_request.open('GET', pageurl+bustcacheparameter, true)

	page_request.send(null)

}



ajaxpageclass.loadpage=function(page_request, divId){

	if (page_request.readyState == 4 && (page_request.status==200 || window.location.href.indexOf("http")==-1)){

		document.getElementById(divId).innerHTML=page_request.responseText

	}

}



ajaxpageclass.getCookie=function(Name){ 

	var re=new RegExp(Name+"=[^;]+", "i"); //construct RE to search for target name/value pair

	if (document.cookie.match(re)) //if cookie found

		return document.cookie.match(re)[0].split("=")[1] //return its value

	return null

}



ajaxpageclass.setCookie=function(name, value){

	document.cookie = name+"="+value

}



ajaxpageclass.getInitialPage=function(divId, pageinfo){

	var persistedpage=this.getCookie(divId)

	var selectedpage=(this.paginatepersist && this.getCookie(divId)!=null)? parseInt(this.getCookie(divId)) : pageinfo.selectedpage

	return (selectedpage>pageinfo.pages.length-1)? 0 : selectedpage //check that selectedpage isn't out of range

}



ajaxpageclass.createBook=function(pageinfo, divId, paginateIds){ //MAIN CONSTRUCTOR FUNCTION

	this.pageinfo=pageinfo //store object containing URLs of pages to fetch, selected page number etc

	this.divId=divId

	this.paginateIds=paginateIds //array of ids corresponding to the pagination DIVs defined for this pageinstance

	//NOTE: this.paginateInfo stores references to various components of each pagination DIV defined for this pageinstance

	//NOTE: Eg: divs[0] = 1st paginate div, pagelinks[0][0] = 1st page link within 1st paginate DIV, prevlink[0] = previous link within paginate DIV etc

	this.paginateInfo={divs:[], pagelinks:[[]], prevlink:[], nextlink:[], previouspage:null, previousrange:[null,null], leftellipse:[], rightellipse:[]}

	this.dopagerange=false

	this.pagerangestyle=''

	this.ellipse='<span style="display:none">'+ajaxpageclass.ellipse+'</span>' //construct HTML for ellipse

	var initialpage=ajaxpageclass.getInitialPage(divId, pageinfo)

	this.buildpagination(initialpage)

	this.selectpage(initialpage)

}



ajaxpageclass.createBook.prototype={



	buildpagination:function(selectedpage){ //build pagination links based on length of this.pageinfo.pages[]

		this.dopagerange=(this.pageinfo.pages.length>ajaxpageclass.pagerange) //Bool: enable limitpagerange if pagerange value is less than total pages available

		this.pagerangestyle=this.dopagerange? 'style="display:none"' : '' //if limitpagerange enabled, hide pagination links when building them

		this.paginateInfo.previousrange=null //Set previousrange[start, finish] to null to start

		if (this.pageinfo.pages.length<=1){ //no 0 or just 1 page

			document.getElementById(this.paginateIds[0]).innerHTML=(this.pageinfo.pages.length==1)? "" : ""

			return

		}

		else{ //construct paginate interface

			var paginateHTML='<div class="pagination"><ul>\n'

			paginateHTML+='<li><a href="#previous" rel="'+(selectedpage-1)+'">«</a></li>\n' //previous link HTML

			for (var i=0; i<this.pageinfo.pages.length; i++){

				var ellipses={left: (i==0? this.ellipse : ''), right: (i==this.pageinfo.pages.length-1? this.ellipse : '')} //if this is 1st or last page link, add ellipse next to them, hidden by default

				paginateHTML+='<li>'+ellipses.right+'<a href="#page'+(i+1)+'" rel="'+i+'" '+this.pagerangestyle+'>'+(i+1)+'</a>'+ellipses.left+'</li>\n'

			}

			paginateHTML+='<li><a href="#next" rel="'+(selectedpage+1)+'">next »</a></li>\n' //next link HTML

			paginateHTML+='</ul></div>'

		}// end construction

		this.paginateInfo.previouspage=selectedpage //remember last viewed page

		for (var i=0; i<this.paginateIds.length; i++){ //loop through # of pagination DIVs specified

			var paginatediv=document.getElementById(this.paginateIds[i]) //reference pagination DIV

			this.paginateInfo.divs[i]=paginatediv //store ref to this paginate DIV

			paginatediv.innerHTML=paginateHTML

			var paginatelinks=paginatediv.getElementsByTagName("a")

			var ellipsespans=paginatediv.getElementsByTagName("span")

			this.paginateInfo.prevlink[i]=paginatelinks[0]

			if (paginatelinks.length>0)

				this.paginateInfo.nextlink[i]=paginatelinks[paginatelinks.length-1]

			this.paginateInfo.leftellipse[i]=ellipsespans[0]

			this.paginateInfo.rightellipse[i]=ellipsespans[1]

			this.paginateInfo.pagelinks[i]=[] //array to store the page links of pagination DIV

			for (var p=1; p<paginatelinks.length-1; p++){

				this.paginateInfo.pagelinks[i][p-1]=paginatelinks[p]

			}

			var pageinstance=this

			paginatediv.onclick=function(e){

				var targetobj=window.event? window.event.srcElement : e.target

				if (targetobj.tagName=="A" && targetobj.getAttribute("rel")!=""){

					if (!/disabled/i.test(targetobj.className)){ //if this pagination link isn't disabled (CSS classname "disabled")

						pageinstance.selectpage(parseInt(targetobj.getAttribute("rel")))

					}

				}

				return false

			}

		}

	},



	selectpage:function(selectedpage){

		//replace URL's root domain with dynamic root domain (with or without "www"), for ajax security sake:

		if (this.pageinfo.pages.length>0){

			var ajaxfriendlyurl=this.pageinfo.pages[selectedpage].replace(/^http:\/\/[^\/]+\//i, "http://"+window.location.hostname+"/")

			ajaxpageclass.connect(ajaxfriendlyurl, this.divId) //fetch requested page and display it inside DIV

		}

		if (this.pageinfo.pages.length<=1) //if this book only contains only 1 page (or 0)

			return //stop here

		var paginateInfo=this.paginateInfo

		for (var i=0; i<paginateInfo.divs.length; i++){ //loop through # of pagination DIVs specified

			//var paginatediv=document.getElementById(this.paginateIds[i])

			paginateInfo.prevlink[i].className=(selectedpage==0)? "prevnext disabled" : "prevnext" //if current page is 1st page, disable "prev" button

			paginateInfo.prevlink[i].setAttribute("rel", selectedpage-1) //update rel attr of "prev" button with page # to go to when clicked on

			paginateInfo.nextlink[i].className=(selectedpage==this.pageinfo.pages.length-1)? "prevnext disabled" : "prevnext"

			paginateInfo.nextlink[i].setAttribute("rel", selectedpage+1)

			paginateInfo.pagelinks[i][paginateInfo.previouspage].className="" //deselect last clicked on pagination link (previous)

			paginateInfo.pagelinks[i][selectedpage].className="currentpage" //select current pagination link

		}

		paginateInfo.previouspage=selectedpage //Update last viewed page info

		ajaxpageclass.setCookie(this.divId, selectedpage)

		this.limitpagerange(selectedpage) //limit range of page links displayed (if applicable)

	},



	limitpagerange:function(selectedpage){

		//reminder: selectedpage count starts at 0 (0=1st page)

		var paginateInfo=this.paginateInfo

		if (this.dopagerange){

			var visiblelinks=ajaxpageclass.pagerange-1 //# of visible page links other than currently selected link

			var visibleleftlinks=Math.floor(visiblelinks/2) //calculate # of visible links to the left of the selected page

			var visiblerightlinks=visibleleftlinks+(visiblelinks%2==1? 1 : 0) //calculate # of visible links to the right of the selected page

			if (selectedpage<visibleleftlinks){ //if not enough room to the left to accomodate all visible left links

				var overage=visibleleftlinks-selectedpage

				visibleleftlinks-=overage //remove overage links from visible left links

				visiblerightlinks+=overage //add overage links to the visible right links

			}

			else if ((this.pageinfo.pages.length-selectedpage-1)<visiblerightlinks){ //else if not enough room to the left to accomodate all visible right links

				var overage=visiblerightlinks-(this.pageinfo.pages.length-selectedpage-1)

				visiblerightlinks-=overage //remove overage links from visible right links

				visibleleftlinks+=overage //add overage links to the visible left links

			}

			var currentrange=[selectedpage-visibleleftlinks, selectedpage+visiblerightlinks] //calculate indices of visible pages to show: [startindex, endindex]

			var previousrange=paginateInfo.previousrange //retrieve previous page range

			for (var i=0; i<paginateInfo.divs.length; i++){ //loop through paginate divs

				if (previousrange){ //if previous range is available (not null)

					for (var p=previousrange[0]; p<=previousrange[1]; p++){ //hide all page links

						paginateInfo.pagelinks[i][p].style.display="none"

					}

				}

				for (var p=currentrange[0]; p<=currentrange[1]; p++){ //reveal all active page links

					paginateInfo.pagelinks[i][p].style.display="inline"

				}

				paginateInfo.pagelinks[i][0].style.display="inline" //always show 1st page link

				paginateInfo.pagelinks[i][this.pageinfo.pages.length-1].style.display="inline" //always show last page link

				paginateInfo.leftellipse[i].style.display=(currentrange[0]>1)? "inline" : "none" //if starting page is page3 or higher, show ellipse to page1

				paginateInfo.rightellipse[i].style.display=(currentrange[1]<this.pageinfo.pages.length-2)? "inline" : "none" //if end page is 2 pages before last page or less, show ellipse to last page

			}

		}

			paginateInfo.previousrange=currentrange

	},



	refresh:function(pageinfo){

	this.pageinfo=pageinfo

	var initialpage=ajaxpageclass.getInitialPage(this.divId, pageinfo)

	this.buildpagination(initialpage)

	this.selectpage(initialpage)

	}

}