var questions = new Array("question1.gif","question2.gif","question3.gif","question4.gif","question5.gif","question6.gif");
	var charts = new Array("pie1.gif","pie2.gif","pie3.gif","bar1.gif","bar2.gif","bar3.gif");

	var currIndex = 0;

	function next() {
		//alert("currIndex" + currIndex);
		if(currIndex +1 >= questions.length) 
			return;

		//increment
		currIndex++; 

		//set images 
		setImage();
	}

	function previous() {
		//alert("currIndex" + currIndex);
		if(currIndex == 0) {
			return;
		}

		//increment
		currIndex--;
		 
		//set images 
		setImage();
	}

	function setImage() {
		var qImages = document.getElementById('question');
		var cImages = document.getElementById('chart');
		qImages.src='images/'+ questions[currIndex];
		cImages.src='images/'+ charts[currIndex];
	}