function ShowMenu(sender) {
    var name = "divM" + sender;
    var menu = document.getElementById(name);
    if (menu.style.display == "block")
        return;
    else {
        hideMenu();
        menu.style.display = "block";
    }
}

function hideMenu() {
    var objTable = document.getElementById("menu");
    var aInput = objTable.getElementsByTagName("div"); //返回数组   
    for (var i = 0; i < aInput.length; i++) {
        aInput[i].style.display = "none";
    }
}