// JavaScript Document

/*
	Developed by Robert Nyman, http://www.robertnyman.com
	Code/licensing: http://code.google.com/p/getelementsbyclassname/
*/	
var getElementsByClassName = function (className, tag, elm){

	/* if (document.getElementsByClassName) {
		getElementsByClassName = function (className, tag, elm) {
			elm = elm || document;
			var elements = elm.getElementsByClassName(className),
				nodeName = (tag)? new RegExp("\\b" + tag + "\\b", "i") : null,
				returnElements = [],
				current;
			for(var i=0, il=elements.length; i<il; i+=1){
				current = elements[i];
				if(!nodeName || nodeName.test(current.nodeName)) {
					returnElements.push(current);
				}
			}
			return returnElements;
		};
	}
	else */ 
if (document.evaluate) {
		getElementsByClassName = function (className, tag, elm) {
			tag = tag || "*";
			elm = elm || document;
			var classes = className.split(" "),
				classesToCheck = "",
				xhtmlNamespace = "http://www.w3.org/1999/xhtml",
				namespaceResolver = (document.documentElement.namespaceURI === xhtmlNamespace)? xhtmlNamespace : null,
				returnElements = [],
				elements,
				node;
			for(var j=0, jl=classes.length; j<jl; j+=1){
				classesToCheck += "[contains(concat(' ', @class, ' '), ' " + classes[j] + " ')]";
			}
			try	{
				elements = document.evaluate(".//" + tag + classesToCheck, elm, namespaceResolver, 0, null);
			}
			catch (e) {
				elements = document.evaluate(".//" + tag + classesToCheck, elm, null, 0, null);
			}
			while ((node = elements.iterateNext())) {
				returnElements.push(node);
			}
			return returnElements;
		};
	}
	else {
		getElementsByClassName = function (className, tag, elm) {
			tag = tag || "*";
			elm = elm || document;
			var classes = className.split(" "),
				classesToCheck = [],
				elements = (tag === "*" && elm.all)? elm.all : elm.getElementsByTagName(tag),
				current,
				returnElements = [],
				match;
			for(var k=0, kl=classes.length; k<kl; k+=1){
				classesToCheck.push(new RegExp("(^|\\s)" + classes[k] + "(\\s|$)"));
			}
			for(var l=0, ll=elements.length; l<ll; l+=1){
				current = elements[l];
				match = false;
				for(var m=0, ml=classesToCheck.length; m<ml; m+=1){
					match = classesToCheck[m].test(current.className);
					if (!match) {
						break;
					}
				}
				if (match) {
					returnElements.push(current);
				}
			}
			return returnElements;
		};
	}
	return getElementsByClassName(className, tag, elm);
};

function PickSubsetSequenced(Q, M) {
    var J, K, L = Q.length, T;
    for (K = L; K > L - M; K--) {
        J = Random(K);
        T = Q[K - 1];
        Q[K - 1] = Q[J];
        Q[J] = T;
    }
    return Q.slice(L - M);
}

function Random(X) {
    return Math.floor(X * (Math.random() % 1));
}

function changeClassNameOf(showNumbers, typeOfElements, theElement, beforeClassName, afterClassName) {
	var myElements = theElement.getElementsByTagName(typeOfElements);
	var myLength = myElements.length;
	var myList = new Array();
	for (i = 0; i < myLength; i++) {
		myElements[i].className += " " + beforeClassName;
		myList.push(myElements[i]);
	}
	
    PickSubsetSequenced(myList, myLength);
	var myShowList = myList.slice(myList.length - showNumbers);
	for(y = 0; y < myShowList.length; y++) {
		myShowList[y].className += afterClassName;
	}
}
function changeDisplayOf(showNumbers, className, theElement, before, after) {
	var myElements = getElementsByClassName(className, 'div', theElement);//className, tag, elm
	var myLength = myElements.length;
	var myList = new Array();
	for (i = 0; i < myLength; i++) {
		myElements[i].style.display = before;
		myList.push(myElements[i]);
	}

    PickSubsetSequenced(myList, myLength);
	var myShowList = myList.slice(myList.length - showNumbers);
	for(y = 0; y < myShowList.length; y++) {
		myShowList[y].style.display = after;
	}


   }