//目录初始化方法
//menuId所选目录，actuatorId所选目录的上级目录
function initializeMenu(menuId, actuatorId) {

    var menu = document.getElementById(menuId);
    var actuator = document.getElementById(actuatorId);
	
	actuator.parentNode.style.backgroundImage = "url(images/leftsign1.gif)";
	
      actuator.onclick = function() {
        var display = menu.style.display;
		this.parentNode.style.backgroundImage =
		   (display == "block") ? "url(images/leftsign1.gif)" : "url(images/leftsign2.gif)";
        menu.style.display = (display == "block") ? "none" : "block";
        return false;
    }
}

//初始化树状目录
 window.onload = function() {
            initializeMenu("product1Menu", "productActuator"); 
			 initializeMenu("EDM1Menu", "EDMActuator");            
			initializeMenu("EBP1Menu", "EBPActuator");
			initializeMenu("solveMenu", "solveActuator");
			initializeMenu("casusMenu", "casusActuator");
				
        }