function goBack() {
		currentCaseStudyNumber = currentCaseStudyNumber - 1;
		if (currentCaseStudyNumber < 0) currentCaseStudyNumber = numberOfCaseStudies - 1;
		updateCaseStudy();
	}
	
	function goForward() {
		currentCaseStudyNumber = currentCaseStudyNumber + 1;
		if (currentCaseStudyNumber == numberOfCaseStudies) currentCaseStudyNumber = 0;
		updateCaseStudy();
	}

	function updateCaseStudy() {
		
		// update screenshot
			document.getElementById('portfolioScreenshot').innerHTML = "<img src='img/screenshots/" + casestudies[currentCaseStudyNumber]['screenshot'] + "' class='screenshotWrapper' alt='" + casestudies[currentCaseStudyNumber]['title'] + "' title='" + casestudies[currentCaseStudyNumber]['title'] + "' />";
		
		// update description
			document.getElementById('portfolioDescription').innerHTML = casestudies[currentCaseStudyNumber]['description'];
		
		// update title
			document.getElementById('portfolioTitle').innerHTML = casestudies[currentCaseStudyNumber]['title'];
		
	}