ALP Popup menu handler
PopupMenuHandler and PopupMenuHandlerNamespace properties are used to specify the script function that will inspect the context menu requests made by the page(s). Note that this technique is not fully compatible with Internet Explorer 4 - see the remarks section for details. Use DisplayPopupMenu method if you want full compatibility with all the supported Internet Explorer versions (4.0 and later). 

Syntax and description

external.PopupMenuHandler - string - Read/Write. Specifies the script function to be called to handle the notification. Only the function name must be specified (no brackets or parameters). For example:

external.PopupMenuHandler = "MyPopupMenuHandler";
In the page function should be defined as:
function MyPopupMenuHandler(firingElment) {
   // Implementation ...
See below what the function must do in order to select the menu.

external.PopupMenuHandlerNamespace - string - Read/Write. Specifies the namespace that holds the function specified in the PopupMenuHandler property. the string syntax is "namespacetype=namespacename". Currently only frame is supported as namespace type. In case of no frames property should be empty (i.e. care about it only if you have frames). Example:

external.PopupMenuHandlerNamespace = "frame=main";
If you have a FRAMESET with a frame called "main" or IFRAME with that name.

The handler function

Function prototype is:
function PopupMenuHanlerFunctionName(elementClicked) { ... }

The parameter elementClicked passes to it reference to the object in the DHTML page clicked by the user. Function is called when user clicks with the right mouse button somewhere in the page(s). By inspecting the passed object function is able to determine what context menu must be used and it must return VarioMenuItem object from the menu tree. For example:

function MyPopupHandler( elClicked ) {
  if (elClicked.tagName == "IMG") return external.Menus.MenuTree.Subs("MyPopupMenus")("ImagePopupMenu");
  if (elClicked.tagName == "P") return external.Menus.MenuTree.Subs("MyPopupMenus")("ParagraphPopupMenu");
  return null; 

This example code selects previously defined branches of the menu tree to be used as context menu for the object depending on its HTML tag type. It selects some menus for the IMG and P elements and returns null for all other elements. Returning null means "don't show context menu". 


If Internet Explorer 4.x is installed on the machine running the ALPFrame handler function receives as elementClicked only whose DHTML elements that are able to gain focus - i.e. links (A tags), form fields (INPUT, SELECT, TEXTAREA), body (BODY). If the element can not be focused then the the first focusing capable element containing the clicked element is returned. Usually this will be the BODY - document itself instead of the clicked element. IE 4.x doesn't support some coordinate mapping features required to implement element recognition safe enough. Using the alternative way - DisplayPopupMenu method is recommended if the compatibility with IE 4.x is a requirement.

Most developers will choose DisplayPopupMenu because its usage is easier. But using popup menu handlers can help to the advanced programmers to safe some work by omitting the code that shows the menu and only implementing a selection routine - the popup menu handler. The same result can be achieved using the DisplayPopupMenu method:

Use the onMouseup DHTML event. Specify a handler routine in the BODY element only:
<BODY onMouseup="MyHandler">
Write the MyHandler function:
function MyHandler() {
  if (event.button != 2) return;
  // If the mouse button pressed is not the right button do nothing
  // Use the event.srcElement to recognize the clicked object
  // For example (as in the above example):
  var popups = external.Menus.MenuTree.Subs("MyPopupMenus");
  switch (elClicked.tagName) {
    case "IMG":
    case "P":

Applies to: external
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