// JavaScript Document
var scrolltotop={
 setting: {startline:1, scrollto: 0, scrollduration:1000, fadeduration:[500, 100]},
 controlHTML: '<img src="../wp-content/themes/debut/images/toHead.png" style="width:24px; height:24px" />', 
 controlattrs: {offsetx:5, offsety:5}, 
 anchorkeyword: '#top',
 state: {isvisible:false, shouldvisible:false},
 scrollup:function(){
  if (!this.cssfixedsupport) 
   this.$control.css({opacity:0}) 
  var dest=isNaN(this.setting.scrollto)? this.setting.scrollto : parseInt(this.setting.scrollto)
  if (typeof dest=="string" && jQuery('#'+dest).length==1)
   dest=jQuery('#'+dest).offset().top
  else
   dest=0
  this.$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 
   mainobj.$body=(window.opera)? (document.compatMode=="CSS1Compat"? $('html') : $('body')) : $('html,body')
   mainobj.$control=$('<div id="topcontrol">'+mainobj.controlHTML+'</div>')
    .css({position:mainobj.cssfixedsupport? 'fixed' : 'absolute', bottom:mainobj.controlattrs.offsety, right:mainobj.controlattrs.offsetx, opacity:0, cursor:'pointer'})
    .attr({title:'返回顶部'})
    .click(function(){mainobj.scrollup(); return false})
    .appendTo('body')
   if (document.all && !window.XMLHttpRequest && mainobj.$control.text()!='') 
    mainobj.$control.css({width:mainobj.$control.width()}) 
   mainobj.togglecontrol()
   $('a[href="' + mainobj.anchorkeyword +'"]').click(function(){
    mainobj.scrollup()
    return false
   })
   $(window).bind('scroll resize', function(e){
    mainobj.togglecontrol()
   })
  })
 }
}
scrolltotop.init()