Activating ActiveX Controls _javascript Tips

Activating an ActiveX control

Release date: 2006-3-29 | update: 2006-3-29

Internet Development Index

Users cannot interact directly with Microsoft ActiveX controls loaded by applets, EMBED, or OBJECT elements. Users can interact with these controls after they activate the user interface for those controls. This article describes how Microsoft Internet Explorer handles ActiveX controls, shows how ActiveX controls can be loaded to activate their interfaces, and also describes how this behavior affects the application of accessibility tools and host WebBrowser controls.

This topic contains the following sections.

Content of this page

	Understanding Control Activation
	To load an interactive control externally
	To programmatically determine whether a control is not activated
	Auxiliary impact
	WebBrowser Control Effects
	Appendix A: DHTML events that are blocked by the control not activated

For additional information about the platform affected by this update, see Internet Explorer ActiveX update.

Understanding Control Activation

An interactive control is an ActiveX control that provides a user interface. When a Web page uses an APPLET,EMBED , or OBJECT element to load an ActiveX control, the user interface for that control is blocked until the user activates it. If a page uses these elements to load multiple controls, each interaction control must be activated separately.

If a control is not active, the following results appear.

•	Dynamic HTML (DHTML) events (such as onblur and onclick) associated with user interaction are blocked. Appendix A lists the DHTML events that are blocked when the control is not activated.
•	The control does not respond to keyboard or mouse-generated window messages, such as Wm_click, wm_keypress, and so on.
•	Overwriting a window (created in the control's OLE site) prevents keyboard and mouse messages from reaching an inactive control.

After you create an inactive control, Internet Explorer uses different techniques to prevent keyboard or mouse window messages from reaching the control. If an inactive control is a window-enabled control (such as an HTML help control), Internet Explorer uses the enablewindow function to disable the window for this inactive control. When a user activates a control with a window, the function activates the disabled window. If an inactive control is a windowless control, such as an Office Web component, the container for the control filters keyboard and mouse messages.

If a control is not activated, it does not respond to user input, but performs an interaction-independent operation. For example, if you open a Web page that uses a Microsoft Windows media Player to play music files, the page will not play music until it is loaded. You can interact with the Windows Media Player only after the user interface for the control is activated, as shown in the following illustration.

note Although controls are not activated to respond to any direct user interaction, they respond to script commands.

To activate an interactive control, you can click the control, or you can use the Tab key to set the focus on the control, and then press SPACEBAR or ENTER. An interactive control loaded from an external script can respond immediately to user interaction without activation.

Some controls with Windows use Windows API functions such as getkeystate and GetCursorPos to determine the state of the keyboard and mouse, and then respond to function results. For these controls only, a prompt appears before the control is run in Internet Explorer. To run the control, the user needs to click the button in the message window before the page is loaded. After loading, the control does not need to be activated. Currently, the following controls have this behavior, but the vendor is continuing to develop new controls that do not have the behavior.

•	Virtools™web Player from Virtools SA
•	Macromedia Shockwave Player™from Adobe Systems Inc.
•	Quicktime™from Apple Computer, Inc.

When loaded from an external script file, these controls do not display hints.

The following illustration shows the prompt dialog box.

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To load an interactive control externally

To create a Web page that loads an interactive control that responds to user input immediately, loads the control from an external script file using Microsoft JScript. You cannot write script elements that are inline with the main HTML page to load controls from outside. If the script is written inline (for example, with the writeln function), the loaded control needs to be activated as if it were loaded by the HTML document itself. To make sure that the control is interactive after loading, use any of the following techniques.

The following example uses document.write to dynamically load controls.

HTML File
 
The next example uses document. createelement Loads an ActiveX control that uses the OBJECT element.
 
important When you use createelement to load an Object element or Embed element to a Web page, be careful to create the element, initialize its properties, add the element to the page's DOM, and then create an ActiveX control to be loaded by the new element. For more information, see the createelement documentation.

HTML File
 
The next example uses the InnerHTML and JScript functions to load ActiveX controls, specifying parameter values.

HTML File

External_script.js
function CreateControl (divID, CLSID, ObjectID,
      WIDTH, HEIGHT, URL, AUTOSTART)
{ C20/>var d = document.getElementById (divID);
 d.innerhtml = 
 ' <object classid= ' + CLSID + ' id= ' + ObjectID + 
 ' width= ' + width + ' height= ' + height + ' >
 <param name= "url" value= ' + URL + ' >
 <param name= ' autostart ' value= ' + autostart + '/> ';
}
 
Because the next example uses the writeln function to insert the script into the original HTML document, the resulting control needs to be activated. To load a control that does not need to be activated, use one of the examples above.

HTML File
 
Warning If the Disable script debugging (Internet Explorer) option is not selected in the Advanced tab of the Internet options in Control Panel, controls created with these techniques still need to be activated.
 

    

 
     

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To programmatically determine whether a control is not activated
 
You cannot use a JScript function or a server-side script to determine whether a control is active. The application hosting the Web Browser Control cannot determine whether a control is active.
 
The control can determine the activation state through the Dispid_ambient_uidead ambient property, which is invoked by IDispatch::Invoke . When this property is changed through iolecontrol::onambientpropertychange , the control that implements the IOleControl interface is notified.
 

    

 
     

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Auxiliary impact
 
When an auxiliary tool encounters an ActiveX control, you can use the object's iaccessible interface to get information about the control. You can use the iaccessible::accdodefaultaction method to activate a control that is not active.
 
The following table describes the results generated by invoking the IAccessible method on an inactive control.
 


    
 
 
     
 
      
 
       
Method
 
       
Description
 
      
 
     
 
 
     
 
      
 
       
Iaccessible::accdodefaultaction
 
       
Activates the control and exposes ActiveX controls or Java applets within the MSAA tree.
 
      
 
      
 
       
Iaccessible::acchittest
 
       
Back to Childid_self
 
      
 
      
 
       
Iaccessible::acclocation
 
       
The location of the underlying ActiveX control or Java Applet
 
      
 
      
 
       
Iaccessible::accnavigate
 
       
Back to E_NotImpl
 
      
 
      
 
       
Iaccessible::accselect
 
       
Back to E_NotImpl
 
      
 
      
 
       
Iaccessible::get_accchild
 
       
Back to S_FALSE
 
      
 
      
 
       
Iaccessible::get_accchildcount
 
       
return 0 and S_OK
 
      
 
      
 
       
Iaccessible::get_accdefaultaction
 
       
Returns "Select this control"
 
      
 
      
 
       
Iaccessible::get_accdescription
 
       
Back to E_NotImpl
 
      
 
      
 
       
Iaccessible::get_accfocus
 
       
Back to E_NotImpl
 
      
 
      
 
       
Iaccessible::get_acchelp
 
       
Returns the ' this control ' inactive. Select the control to activate and use it.
 
      
 
      
 
       
Iaccessible::get_acchelptopic
 
       
No change-return to E_NOTIMPL
 
      
 
      
 
       
Iaccessible::get_acckeyboardshortcut
 
       
No change-Delegate the object. If there are no objects, the method returns E_NOTIMPL.
 
      
 
      
 
       
IAccessible::get_accName
 
       
Return to "Inactive control"
 
      
 
      
 
       
Iaccessible::get_accparent
 
       
No change-Returns the most recent accessible element in the parent chain.
 
      
 
      
 
       
Iaccessible::get_accrole
 
       
Back to Role_system_pushbutton
 
      
 
      
 
       
Iaccessible::get_accselection
 
       
Back to E_NotImpl
 
      
 
      
 
       
Iaccessible::get_accstate
 
       
Returns the current state of an object. This state always includes state_system_focusable
 
      
 
      
 
       
Iaccessible::get_accvalue
 
       
Back to E_NotImpl
 
      
 
      
 
       
IAccessible::p ut_accname
 
       
Back to E_NotImpl
 
      
 
      
 
       
IAccessible::p Ut_accvalue
 
       
Back to E_NotImpl
 
      
 
     

    
 

    

 
     


    
 
For information about activated controls or controls that you do not need to activate, see the Active Accessibility SDK.
 
Note The utility should refresh after the default action is triggered to correctly display the data of the ActiveX control and its child controls, if any.
 

    

 
     

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WebBrowser Control Effects
 
By default, custom applications that host WebBrowser control do not block interactive ActiveX controls that are loaded by applets,EMBED , or OBJECT elements. The control is not activated to apply only to the following applications.
 


    
 
 
     
 
      
 
       
•
 
       
Windows Explorer
 
      
 
      
 
       
•
 
       
Internet Explorer
 
      
 
      
 
       
•
 
       
MSN Explorer
 
      
 
      
 
       
•
 
       
Aol®explorer
 
      
 
      
 
       
•
 
       
aol®8.0
 
      
 
      
 
       
•
 
       
aol®9.0
 
      
 
      
 
       
•
 
       
CompuServe 2000
 
      
 
      
 
       
•
 
       
Aim®
 
      
 
      
 
       
•
 
       
Maxthon Browser
 
      
 
      
 
       
•
 
       
Netcaptor
 
      
 
      
 
       
•
 
       
Browse3d
 
      
 
      
 
       
•
 
       
Macromedia Dreamweaver
 
      
 
      
 
       
•
 
       
Macromedia Contribute
 
      
 
      
 
       
•
 
       
Netscape®8 (when using Internet Explorer as a rendering engine)
 
      
 
     

    
 
To match the behavior of Internet Explorer in your application, add the Dochostuiflag_enable_activex_inactivate_mode flag to the dochostuiinfo structure of the dwflags parameter, as shown in the following example.

HRESULT GetHostInfo (dochostuiinfo *pinfo)
{
 ...
 pinfo->cbsize = sizeof (dochostuiinfo);
 Pinfo->dwflags = {Other dochostuiflags} | 
  Dochostuiflag_enable_activex_inactivate_mode; 
 ...
 return S_OK;
}
 
You can also enable interactive control blocking by adding the application's process name to the following registry key.

HKEY_LOCAL_MACHINE (or HKEY_CURRENT_USER)
SOFTWARE
Microsoft
Internet Explorer
Main
FeatureControl
feature_enable_activex_inactivate_mode
process_name.exe= (DWORD) 0x00000001
 
Note Because the user can modify the registry, the Dochostuiinfo flag is the preferred method of enabling interactive control blocking.
 
By default, an application can register to incorporate ActiveX control activation. For more information, consult your Technical Account manager or contact Microsoft's product support department.
 

    

 
     

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Appendix A: DHTML events that are blocked by the control not activated
 
The following table lists the DHTML events that are blocked when an ActiveX control is not activated.
 


    
 
 
     
 
 
     
 
      
 
       
OnActivate
 
       
OnDragLeave
 
       
onmouseout
 
      
 
      
 
       
Onbeforeactivate
 
       
OnDragOver
 
       
onmouseover
 
      
 
      
 
       
Onbeforecopy
 
       
Ondragstart
 
       
OnMouseUp
 
      
 
      
 
       
Onbeforecut
 
       
OnDrop
 
       
OnMouseWheel
 
      
 
      
 
       
Onbeforedeactivate
 
       
onfocus
 
       
OnMove
 
      
 
      
 
       
Onbeforepaste
 
       
Onfocusin
 
       
Onmoveend
 
      
 
      
 
       
Onblur
 
       
Onfocusout
 
       
Onmovestart
 
      
 
      
 
       
OnClick
 
       
OnHelp
 
       
OnPage
 
      
 
      
 
       
OnContextMenu
 
       
OnKeyDown
 
       
Onpaste
 
      
 
      
 
       
Oncontrolselect
 
       
onkeypress
 
       
OnResize
 
      
 
      
 
       
Oncopy
 
       
OnKeyUp
 
       
Onresizeend
 
      
 
      
 
       
Oncut
 
       
Onlosecapture
 
       
Onresizestart
 
      
 
      
 
       
OnDblClick
 
       
OnMouseDown
 
       
Onscroll
 
      
 
      
 
       
OnDeactivate
 
       
Onmouseenter
 
       
Onselectstart
 
      
 
      
 
       
Ondragend
 
       
OnMouseLeave
 
       
-
 
      
 
      
 
       
OnDragEnter
 
       
OnMouseMove
 
       
-