function toggle_about() {
	if (document.getElementById("box1") != null) {	
			var box1 = document.getElementById("box1");
			var box2 = document.getElementById("box2");
			var about_link = document.getElementById("5forces-about");
			var back_link = document.getElementById("5forces-back");
			
			about_link.onclick = function() {
				box1.style.display = "none";
				box2.style.display = "block";
				return false;
			}
			back_link.onclick = function() {
				box2.style.display = "none";
				box1.style.display = "block";
				return false;
			}
		}
}


function addLoadEvent(func) {
	var oldonload = window.onload;
	if (typeof window.onload != 'function') {
		window.onload = func;
	} else {
		window.onload = function() {
			if (oldonload) {
				oldonload();
			}
			func();
		}
	}
}

addLoadEvent(toggle_about);