階層 後台點擊特效
建立DIV，設定OnClick事件
<Div ID="Main" OnClick="select_menu('Main')">
<Div ID="MainDIV">
<Div ID="MainDIV">
function select_menu(num){ document.getElementById(num+"DIV").style.display= document.getElementById(num+"DIV").style.display == '' ? "none" : ''; 
}