<a href="javascript:if(confirm('您确定要返回吗？'))history.back();"><img src="img/fh.gif"/></a>

?

<script language="javascript" type="text/javascript">
		function isExit() {
			var msg = "您确定要退出吗？";
			if (confirm(msg)==true){
			parent.location.href="<%=path%>/logout.jsp";
			}else{
			return false;
			}
		}
	</script>
	
	<%
	session.setAttribute("loginUser", null);
%>

?