参考链接：
http://www.terrainformatica.com/2006/08/h-smile-core-popup-and-context-menus-htmlayout-and-sciter-engines/

代码示例：

import win.ui;
/*DSG{{*/
var winform = ..win.form( text="HTMLayout 使用右键菜单";bottom=399;parent=...;right=599;border="resizable" )
winform.add(  )
/*}}*/

import web.layout;
wbLayout = web.layout(winform)

wbLayout.html = /**  
<body> 

鼠标右键点击下面的按钮显示右键菜单:<br />  
<button class="with-context-menu">右键点击这里</button>    

<menu.context id="menuId">
  <li id="i1">First item</li>
  <li id="i2">Second item</li>
  <li id="i3">Third item</li>
  <li id="i4">Fourth item</li>
  <li>Sub menu
     <menu>
     <li id="i5">5 item</li>
     <li id="i6">6 item</li>
     </menu>  
  </li> 
</menu>

</body> 
**/ 

wbLayout.css = /**
.with-context-menu {  
  context-menu: selector(menu#menuId); /*selector函数的参数是指定右键菜单的CSS选择器*/
} 

menu{
    width: max-intrinsic; /*内容的最大宽度,可以超出屏幕*/
} 
**/
    
//右键菜单触发下面的函数
wbLayout.onMenuItemClick = function (ltTarget,ltEle,reason,behaviorParams) {
        
        //得到当前弹出菜单的节点
        var ltSource = ..web.layout.element( behaviorParams.he )
        
        //ltEle是菜单,ltTarget是点击的菜单项目
    winform.msgbox("你点击了菜单 " + ltTarget.innerText )
}

//弹出菜单前触发
wbLayout.onPopupRequest = function (ltTarget,ltEle,reason,behaviorParams) {

        //得到当前弹出菜单的节点
        var ltSource = ..web.layout.element( behaviorParams.he )
        ltSource.innerText = "已弹出菜单"
        
        //ltEle是菜单对象
}

wbLayout.onPopupDismissed = function (ltTarget,ltEle,reason,behaviorParams) {

        //得到当前弹出菜单的节点
        var ltSource = ..web.layout.element( behaviorParams.he )
        ltSource.innerText = "已关闭菜单"
        
        //ltEle是菜单对象
}

winform.show() 
win.loopMessage()