function toggleFeature(descId) {
  for (var i = 0; i < 5; i++) {
    var tmpId = "block"+i;
    var el = document.getElementById(tmpId);
    var navEl = document.getElementById(el.getAttribute("parentId"));
    el.style.display = (tmpId == descId) ? "block" : "none";
    navEl.className = (navEl.getAttribute("descId") == descId) ? "current" : "";
  }
}

function updateFlockHeaders(flockHeader, flockSubHeader) {
  document.getElementById("flockHeader").innerHTML = flockHeader;
  document.getElementById("flockSubHeader").innerHTML = flockSubHeader;
}

function updateFeatureTxt(els, obj, prefix, titleAttribute) {
  for (var i = 0; i < els.length; i++) {
    els[i].className = (obj.id == els[i].id) ? "current" : "";
    if(titleAttribute.toString() == "defaultTxt") {
      els[i].className = "";
    }
  }
  if (!obj.getAttribute("featureTxt")) {
    obj.setAttribute("featureTxt","");
  }
  document.getElementById(prefix+"ExtraInfo").innerHTML = obj.getAttribute(titleAttribute);
  document.getElementById(prefix+"ExtraInfoTxt").innerHTML = obj.getAttribute("featureTxt");
}

function initFeatures() {
  //switch main welcome graphic for diff browser
	var appVer = navigator.appVersion.toLowerCase();
	if (appVer.indexOf('mac') == -1) {
	  document.getElementById("feature-main").className = "feature-image-win";
	} else {
	   document.getElementById("feature-main").className = "feature-image-mac";
	}
  //feature navigation
  var els = document.getElementById("tour-options").childNodes;
  for (var i = 0; i < els.length; i++) {
    els[i].onclick = function() {
      this.className = "current";
      toggleFeature(this.getAttribute("descId"));
      updateFlockHeaders(this.getAttribute("flockHeader"),
                         this.getAttribute("flockSubHeader"));
      inst('home/nav/' + this.getAttribute('inst'), this.getAttribute('inst'));
    }
    els[i].onmouseover = function() {
      this.childNodes[1].className = "currentHover";
    }
    els[i].onmouseout = function() {
      this.childNodes[1].className = "";
    }    
  }
  //share easily web clipboard, uploader, blog editor
  var elShareExtra = document.getElementById("share-other");
  var elsShare = elShareExtra.childNodes;
  for (var i = 0; i < elsShare.length; i++) {
    elsShare[i].onmouseover = function() {
      this.className = "current";
      updateFeatureTxt(elsShare, this, "share", "featureHeader");
    }
  }
  //restore default text
  document.getElementById("share-hotzone").onmouseout = function(event) {
    updateFeatureTxt(elsShare,
                     document.getElementById("shareExtraInfo"),
                     "share",
                     "defaultTxt");
  }
  
  //feed reader, media minibar extra info
  var elExtra = document.getElementById("discover-other");
  var elsDiscover = elExtra.childNodes;
  for (var i = 0; i < elsDiscover.length; i++) {
    elsDiscover[i].onmouseover = function() {
      this.className = "current";
      updateFeatureTxt(elsDiscover, this, "discover","featureHeader");
    }
  }
  //restore default text
  document.getElementById("discover-hotzone").onmouseout = function(event) {
    updateFeatureTxt(elsDiscover,
                     document.getElementById("discoverExtraInfo"),
                     "discover",
                     "defaultTxt");
  }
  //Yahoo extra info
  var elExtra = document.getElementById("new-other");
  var elsYahoo = elExtra.childNodes;
  for (var i = 0; i < elsYahoo.length; i++) {
    elsYahoo[i].onmouseover = function() {
      this.className = "current";
      updateFeatureTxt(elsYahoo, this, "new","featureHeader");
    }
  }
  //restore default text
  document.getElementById("new-hotzone").onmouseout = function(event) {
    updateFeatureTxt(elsYahoo,
                     document.getElementById("newExtraInfo"),
                     "new",
                     "defaultTxt");
  }  
}
window.onload = initFeatures;