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:5, scrollto: 0, scrollduration:1000, fadeduration:[500, 100]},
			controlHTML: '<div id="top-link">Ir ao topo</div>', //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: '#top', //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)
				if (typeof dest=="string" && 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()