等待层

        /**
         * 等待层
         */
        setWaitPanel:function(){
            if(document.getElementById("loader_container")!=null){
                return;
            }

            var sWidth = document.body.offsetWidth;
            var sHeight = document.body.scrollHeight;
            panel = document.createElement("div");
            panel.setAttribute(‘id‘, ‘bgDiv‘);
            panel.setAttribute(‘class‘, ‘msgCover‘);
            panel.style.width = sWidth + "px";
            panel.style.height = sHeight + "px";
            document.body.appendChild(panel);

            obj1 = document.createElement("div");
            obj1.setAttribute("id","loader_container");

            var obj2 = document.createElement("div");
            obj2.setAttribute("id", "loader");
            document.body.appendChild(obj1);
            document.getElementById("loader_container").appendChild(obj2);

            var obj3 = document.createElement("div");
            obj3.setAttribute("id","load_img");
            document.getElementById("loader").appendChild(obj3);

            var obj4 = document.createElement("div");
            obj4.setAttribute("id","load_msg");
            obj4.innerHTML = "载入中...";
            document.getElementById("loader").appendChild(obj4);
        },

        /**
         * 清除等待层
         */
        clearWaitPanel:function(){
            document.body.removeChild(panel);
            document.body.removeChild(obj1);
        }
    };
=================================
提交时设置等待层，显示数据后清除等待层
.msgCover {
    background: none repeat scroll 0 0 #777;
    opacity: 0.65;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 10000;
}
#loader_container {
    text-align: center;
    position: absolute;
    top: 200px;
    width: 100%;
    left: 0;
    z-index: 10001;
}
#loader {
    font-size: 11.5px;
    background-color: #FFFFFF;
    padding: 10px 0;
    margin: 0 auto;
    height: 18px;
    width: 120px;
    border: 1px solid #5a667b;
    z-index: 2;
    -moz-border-radius: 5px;
    -webkit-border-radius: 5px;
}

#load_img {
    background-image: url("../images/wait.gif");
    background-size: 16px 16px;
    background-repeat: no-repeat;
    float: left;
    height: 22px;
    margin: 2px 0 0 10px;
    width: 23px;
}

#load_msg {
    float: left;
    margin: 3px 0;
}

============用法=============
提交后设置等待层    SA.setWaitPanel();
数据响应返回后清除等待层    SA.clearWaitPanel();