function expand_collapse(section) {
	var header=document.getElementById(section+"_header");
	var body=document.getElementById(section+"_body");
	var image=document.getElementById(section+"_image");
	if (body.style.display=="none") {
		body.style.display="block";
		image.src="../images/collapse.png";
		image.alt="Collapse";
	}else {
		body.style.display="none";
		image.src="../images/expand.png";
		image.alt="Expand";
	}
}