Tutorial: Botão Voltar ao Topo

Olá pessoal, sentiram saudades? HAHA

Eu estava percebendo que aqui no blog estava faltando uma coisa importante, que eu sempre sinto falta em outros sites, mas eu sempre esquecia o que era. HAHA

Mas hoje eu lembrei e já coloquei ( talvez eu mudo a imagem ), que é aquele botão que a página para o topo, sabe?

Procurei em alguns blogs e encontrei no Cheirinho Doce o código abaixo:

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>

<script type='text/javascript' language='Javascript'>

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 (1=top).

setting: {startline:100, scrollto: 0, scrollduration:1000, fadeduration:[500, 100]},

controlHTML: '<img src="URL_DA_IMAGEM"/>', //HTML for control, which is auto wrapped in DIV w/ ID="topcontrol"

controlattrs: {offsetx:5, offsety:5}, //offset of control relative to right/ center 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.scrollRight() + $window.width() - this.$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()

</script>