//** 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'):
//** v2.0 (Updated by M.TRY 11/12/2009)
//** 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. 
//** a) Now uses external parameters
//** b) fixed scroll to section to work
// NORMAL SETTINGS FOR THE FOLLOWING
// startline:100
// scrollto:0
// scrollduration:1000
// fadeduration:[500, 100]
// controlHTML: '<img src="./images/up.png" style="width:48px; height:48px">', //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 corner
// anchorkeyword: '#scrolltotop', //Enter href value of HTML anchors on the page that should also act as "Scroll Up" links

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:stt_startline, scrollto:stt_scrollto, scrollduration:stt_scrollduration, fadeduration:[500, 100]},
	controlHTML:stt_controlimg, //HTML for control, which is auto wrapped in DIV w/ ID="topcontrol"
	controlattrs:{offsetx:stt_offsetx, offsety:stt_offsety}, //offset of control relative to right/ bottom of window corner
	anchorkeyword: stt_anchorkeyword, //Enter href value of HTML anchors on the page that should also act as "Scroll Up" links

	state: {isvisible:false, shouldvisible:false},

	scrollup:function(){
		if (!this.cssfixedsupport){ //if control is positioned using JavaScript
			this.$control.css({opacity:0}); //hide control immediately after clicking it
			}
		var dest=isNaN(this.setting.scrollto)? this.setting.scrollto : parseInt(this.setting.scrollto,10);
		if (typeof dest=="string"){
		 if (jQuery('#'+dest).length==1){ //check element set by string exists
			dest=jQuery('#'+dest).offset().top;
			}else{
			dest=0;
			}
			}
		this.$body.animate({scrollTop: dest}, this.setting.scrollduration);
	},

	keepfixed:function(){
		var $window=jQuery(window);
		var controlx=$window.scrollLeft() + $window.width() - this.$control.width() - this.controlattrs.offsetx;
		var controly=$window.scrollTop() + $window.height() - this.$control.height() - this.controlattrs.offsety;
		this.$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 : false;
		if (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($){
			var mainobj=scrolltotop;
			var iebrws=document.all;
			mainobj.cssfixedsupport=!iebrws || iebrws && document.compatMode=="CSS1Compat" && window.XMLHttpRequest; //not IE or IE7+ browsers in standards mode
			mainobj.$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 text
				mainobj.$control.css({width:mainobj.$control.width()}); //IE6- seems to require an explicit width on a DIV containing text
				}
			mainobj.togglecontrol();
			$('a[href="' + mainobj.anchorkeyword +'"]').click(function(){
				mainobj.scrollup();
				return false;
			});
			$(window).bind('scroll resize', function(e){
				mainobj.togglecontrol();
			});
		});
	}
};
scrolltotop.init();