var doc; // global reference to XML document
var browser = ""; // holds browser flag
var openingElem = '';
var closingElem = '';
var openingId = '';
var closingId = '';
var totalItr = 10;
var itr = 0;
var tid = '';
var rnum = 0;
var schema={
   rowtag: "student",
   columns: [{tagname: "name", label:"name"},
	   	     {tagname: "pic", label:"pic"},
			 {tagname: "text", label:"text"},
			]
};

function startSlide(index){
  // to make sure bar 4 slides properly - need a left box
  // and an opening image
  document.getElementById("bar4img").src = "images/students/gracemuganda.jpg";
  document.getElementById("bar4img").style.display = "none";
  document.getElementById("leftbox4").src = "images/students/gracemugandabox.jpg";
  document.getElementById("leftbox4").style.display = "none";
  if (openingId == 4){ /* stop student images from displaying */
    clearTimeout(tid);
   	document.getElementById("bar4img").style.display = 'none';
    document.getElementById("bar4img").src = ''; 
  }
  closingId = openingId;
  openingId = index;
  if (closingId == openingId)
      openingId = '';
  openingElem = (openingId == '') ? null : document.getElementById("bar" + openingId);
  closingElem = (closingId == '') ? null : document.getElementById("bar" + closingId);
  setTimeout("slideWindow()", 30); 
}

function slideWindow(){
   itr++;
   if (itr < totalItr){ /* slide window */
      if(closingElem != null){
	 	 document.getElementById("bar" + closingId + "img").style.display = 'none';
		 document.getElementById("leftbox" + closingId).style.display = 'none';
         closingElem.style.paddingRight = (450 - (itr*38)) + 'px';
      }
      if(openingElem != null){
	     document.getElementById("leftbox" + openingId).style.display = 'inline'; 
	     document.getElementById("leftbox" + openingId).style.paddingRight = (itr*38) + 'px';	
	  }
      setTimeout("slideWindow()", 30);
   }
   else{  /* stop sliding */
      itr = 1;
      if(closingElem != null){
		document.getElementById("bar" + closingId + "img").style.display = 'none';
		document.getElementById("leftbox" + closingId).style.display = 'none';
		closingElem.style.paddingRight = 0;
	  }
	  if(openingElem != null){
			document.getElementById("bar" + openingId + "img").style.display = 'inline';
			document.getElementById("leftbox" + openingId).style.paddingRight = 0;
	        if (openingId == "4"){
				rnum = 0;
				loadXMLStudents("students.xml");
	    		startStudents();
	    	}
	  }
   }
}

function startStudents(){
    tid = setTimeout("showStudents()", 10000);
}

function showStudents(){
    var xmlrows, xmlrow, xmlcell, name, pic, text;
	xmlrows = doc.getElementsByTagName(schema.rowtag);
	//rnum = Math.floor(Math.random()*xmlrows.length);
	if (rnum == xmlrows.length-1)
		rnum = 0;
	else
	    rnum++;
    xmlrow = xmlrows[rnum];
	//xmlcell = xmlrow.getElementsByTagName(schema.columns[0].tagname)[0]; // name
    //name = xmlcell.firstChild.data;
	xmlcell = xmlrow.getElementsByTagName(schema.columns[1].tagname)[0]; // pic
    pic = "images/students/" + xmlcell.firstChild.data;  
	xmlcell = xmlrow.getElementsByTagName(schema.columns[2].tagname)[0]; // text
    text = "images/students/" + xmlcell.firstChild.data;
	document.getElementById("bar4img").src = pic;
	document.getElementById("leftbox4").src = text;
	tid = setTimeout("showStudents()", 13000);
}
   
function loadXMLStudents(url){
	   // IE and FF work differently so must test for browser type
		if (window.ActiveXObject){ // IE
		   browser = "IE";
		   // the next statement will create an XML document object
		   doc = new ActiveXObject("Msxml2.DOMDocument.6.0"); 
	       doc.async = false;  // synchronous loading
		   doc.load(url); // loads the document referenced by parameter
		}
		// the same basic statements are used below for Firefox
		else{ // if(document.implementation && document.implementation.createDocument){
		   browser = "FF";
		   doc = document.implementation.createDocument("", "", null);
		   doc.load(url);
  	 	}
	//	else
	//	   alert('Script not supported by your browser');
}