$(document).ready(function(){
	//hide the all of the element with class msg_body
	$(".msg_body").hide();
	//toggle the componenet with class msg_body
	$(".msg_head").click(function(){
		if ($(this).next(".msg_body").is(":hidden")) {
			$(".msg_body").hide();
		}

		$(this).next(".msg_body").slideToggle(300);
	});
});