// -------------------------------------------------------------------
// createAjaxObj()
// -------------------------------------------------------------------
function createAjaxObj(){
  var httprequest=false
  if (window.XMLHttpRequest){ // if Mozilla, Safari etc
    httprequest=new XMLHttpRequest()
    if (httprequest.overrideMimeType)
      httprequest.overrideMimeType('text/xml')
  }
  else if (window.ActiveXObject){ // if IE
    try {
      httprequest=new ActiveXObject("Msxml2.XMLHTTP");
    } 
    catch (e){
      try{
        httprequest=new ActiveXObject("Microsoft.XMLHTTP");
        }
      catch (e){}
    }
  }
  return httprequest
}

// -------------------------------------------------------------------
// ajax_ticker(xmlfile, divId, divClass, delay, optionalfadeornot)
// -------------------------------------------------------------------
function ajax_ticker(xmlfile, divId, divClass, delay, fadeornot){
  this.xmlfile=xmlfile //Variable pointing to the local ticker xml file (txt)
  this.tickerid=divId //ID of ticker div to display information
  this.delay=delay //Delay between msg change, in miliseconds.
  this.mouseoverBol=0 //Boolean to indicate whether mouse is currently over ticker (and pause it if it is)
  this.pointer=0
  this.opacitystring=(typeof fadeornot!="undefined")? "width: 100%; filter:progid:DXImageTransform.Microsoft.alpha(opacity=100); -moz-opacity: 1" : ""
  if (this.opacitystring!="") this.delay+=500 //add 1/2 sec to account for fade effect, if enabled
    this.opacitysetting=0.2 //Opacity value when reset. Internal use.
  this.messages=[] //Arrays to hold each message of ticker
  this.ajaxobj=createAjaxObj()
  document.write('<div id="'+divId+'" class="'+divClass+'"><div style="'+this.opacitystring+'">Obteniendo notas...</div></div>')
  this.getXMLfile()
}

// -------------------------------------------------------------------
// getXMLfile()
// -------------------------------------------------------------------
ajax_ticker.prototype.getXMLfile=function(){
  if (this.ajaxobj){
    var instanceOfTicker=this
    var url=this.xmlfile+"?rand="+new Date().getTime()
    this.ajaxobj.onreadystatechange=function(){instanceOfTicker.initialize()}
    this.ajaxobj.open('GET', url, true)
    this.ajaxobj.send(null)
  }
}

// -------------------------------------------------------------------
// initialize()- Initialize ticker method.
// -------------------------------------------------------------------
ajax_ticker.prototype.initialize=function(){ 
  if (this.ajaxobj.readyState == 4){ //if request of file completed
    if (this.ajaxobj.status==200 || window.location.href.indexOf("http")==-1){ //if request was successful
      this.contentdiv=document.getElementById(this.tickerid).firstChild //div of inner content that holds the messages
      var xmldata=this.ajaxobj.responseText
      this.contentdiv.style.display="none"
      this.contentdiv.innerHTML=xmldata
      if (this.contentdiv.getElementsByTagName("div").length==0){ //if no messages were found
        this.contentdiv.innerHTML="<b>Error</b> fetching remote ticker file!"
        return
      }
      var instanceOfTicker=this
      document.getElementById(this.tickerid).onmouseover=function(){instanceOfTicker.mouseoverBol=1}
      document.getElementById(this.tickerid).onmouseout=function(){instanceOfTicker.mouseoverBol=0}
      if (window.attachEvent) //Clean up loose references in IE
        window.attachEvent("onunload", function(){instanceOfTicker.contentdiv=instanceOfTicker.ajaxobj=null})
      //Cycle through XML object and store each message inside array
      for (var i=0; i<this.contentdiv.getElementsByTagName("div").length; i++){
        if (this.contentdiv.getElementsByTagName("div")[i].className=="message")
          this.messages[this.messages.length]=this.contentdiv.getElementsByTagName("div")[i].innerHTML
      }
      this.contentdiv.innerHTML=""
      this.contentdiv.style.display="block"
      this.rotatemsg()
    }
  }
}

// -------------------------------------------------------------------
// rotatemsg()- Rotate through ticker messages and displays them
// -------------------------------------------------------------------
ajax_ticker.prototype.rotatemsg=function(){
  var instanceOfTicker=this
  if (this.mouseoverBol==1) //if mouse is currently over ticker, do nothing (pause it)
    setTimeout(function(){instanceOfTicker.rotatemsg()}, 100)
  else{ //else, construct item, show and rotate it!
    this.fadetransition("reset") //FADE EFFECT- RESET OPACITY
    this.contentdiv.innerHTML=this.messages[this.pointer]
    this.fadetimer1=setInterval(function(){instanceOfTicker.fadetransition('up', 'fadetimer1')}, 100) //FADE EFFECT- PLAY IT
    this.pointer=(this.pointer<this.messages.length-1)? this.pointer+1 : 0
    setTimeout(function(){instanceOfTicker.rotatemsg()}, this.delay) //update container periodically
  }
}

// -------------------------------------------------------------------
// fadetransition()- cross browser fade method for IE5.5+ and Mozilla/Firefox
// -------------------------------------------------------------------
ajax_ticker.prototype.fadetransition=function(fadetype, timerid){
  var contentdiv=this.contentdiv
  if (fadetype=="reset")
    this.opacitysetting=0.2
  if (contentdiv.filters && contentdiv.filters[0]){
    if (typeof contentdiv.filters[0].opacity=="number") //IE6+
      contentdiv.filters[0].opacity=this.opacitysetting*100
    else //IE 5.5
      contentdiv.style.filter="alpha(opacity="+this.opacitysetting*100+")"
  }
  else if (typeof contentdiv.style.MozOpacity!="undefined" && this.opacitystring!=""){
    contentdiv.style.MozOpacity=this.opacitysetting
  }
  else
    this.opacitysetting=1
  if (fadetype=="up")
    this.opacitysetting+=0.1
  if (fadetype=="up" && this.opacitysetting>=1)
    clearInterval(this[timerid])
}