Frequently Asked Questions About Developing Web Pages Using ActiveX Controls
What is an ActiveX control?
ActiveX controls are reusable software components developed by software vendors. These controls can be used to quickly add specialized functionality to Web sites, desktop applications, and development tools. For example, a stock ticker control can be used to add a live stock ticker to a Web page, or an animation control can be used to add animation features.
Today, there are more than 1,000 commercially available ActiveX controls, which can be created using a variety of programming languages such as C, C++, the next version of Visual Basic®, and Microsoft Visual J++, the company's Visual Java development environment. Once created, ActiveX controls can be used by designers and developers as prefabricated components to create custom applications. Using ActiveX controls in such a manner does not require knowledge of how the component was created, and in many cases requires no programming whatsoever.
Internet Explorer 3.0 is the first Web browser to support ActiveX controls in Web pages. ActiveX controls can also be viewed in Mosaic and in the Netscape Navigator using the ActiveX plug-in for Netscape (see http://www.ncompass.com ).
Can Netscape Navigator Display ActiveX Controls?
Yes, Netscape Navigator can display ActiveX controls using the ActiveX plug-in for Netscape. This plug-in is available in a beta version from Ncompass Labs at http://www.ncompass.com . Also, Internet Explorer 3.0 and the Mosaic Web browser can display ActiveX controls.
Which tools are available today for designing Web pages using ActiveX controls?
You can use the ActiveX Control Pad to easily insert ActiveX controls into your HTML Web pages. Download a free beta copy of the ActiveX Control Pad from the ActiveX Control Pad pages on this site. To learn how to use this tool, follow the ActiveX Control Pad tutorial provided on that page. SoftQuad’s HoTMetaL Pro also offers support for working with ActiveX controls in HTML pages, and over the coming months many other Web authoring tools from Microsoft and third parties will support authoring Web pages with ActiveX controls.
Do I need to be a programmer to use ActiveX controls?
Knowledge of a scripting language such as Visual Basic Scripting Edition (VBScript) or JavaScript™ is helpful, but not required. Some controls require some amount of scripting in order to be fully integrated into a Web page, but many others do not. The ActiveX Control Pad allows even non-programmers to insert many controls by simply pointing and clicking.
When I create a Web page that includes an ActiveX control, how does that control get installed and displayed on a user's machine when they browse my page?
When Internet Explorer 3.0 encounters a Web page with an ActiveX control (or multiple controls), it first checks the user's local system registry to find out if that component is available on their machine. If it is, Internet Explorer 3.0 displays the Web page and activates the control. If the control is not already installed on the user’s computer, Internet Explorer 3.0 automatically finds and installs the component over the Web, based on a location specified by the developer creating the page.
How do I specify a location on the Web so a control will be automatically downloaded to a user’s computer when they browse my page?
The Web page developer provides this information by setting the CODEBASE property for the control. When using the ActiveX Control Pad, you can easily set this property using the visual property table in the Object Editor. Specify a URL location or set of locations where the control can be found and downloaded on the Internet. Internet Explorer 3.0 will then use this information to locate the control and download the component automatically. After the download, the Web page will be displayed. See the "Safe Web Surfing with the Internet Component Download Service" article in the July 1996 edition of the Microsoft Systems Journal for detailed information on how this works. Note that for many Microsoft-supplied controls (such as the HTML Layout Control), no CODEBASE is necessary since there is an ActiveX Object Index that will automatically find the control based on the CLSID (a unique identifier for a control).
Is the user notified that a component is being downloaded?
Yes. When a component needs to be downloaded, Internet Explorer 3.0, by default, will display a message notifying the user of the download. The user can choose to cancel the download or proceed. If the control has been digitally signed, a digital certificate will provide the name of the software vendor supplying the control and will verify that the control has not been tampered with. A control can be digitally signed by the software developer when it is created. The information is carried by the control itself, so the digital certificate will be displayed automatically before downloading with no development work required by the person who utilizes that control on a Web page. (See the Code Signing page on this site for more information on digital signatures.)
Where are controls installed when they are downloaded?
By default, controls are downloaded into an ActiveX control cache located in the \windows\occache directory.
What if a new version of the control is created? How will Internet Explorer know to download the new version if the user already has the previous version of the control on their computer?
The Component Download Service in Internet Explorer 3.0 supports versioning, so that new versions of the control can be detected and automatically downloaded as required. See the "Safe Web Surfing with the Internet Component Download Service" article in the July 1996 edition of the Microsoft Systems Journal for detailed information on how this works.
What about the licensing of ActiveX controls? Once users download a control, can they use it in their own Web pages as well?
ActiveX controls include a mechanism to prevent the unlicensed use of controls in Web pages. Today, this mechanism is supported in development tools such as Visual Basic and Microsoft Access, and is also supported in the beta 2 release of Internet Explorer 3.0. The licensing mechanism works by allowing controls to be distributed with either a developer license, or with a runtime license. With a developer license, a user can use the control for development purposes in developer tools such as Visual Basic, the ActiveX Control Pad, and similar tools. With a runtime license, the user can only view the control within an existing application or Web page, but cannot insert the control into a tool for further development purposes. Supporting the licensing mechanism is up to the individual control vendor. Some control vendors choose not to implement the licensing mechanism, so their controls can be used for development purposes by anyone once they are installed on the computer. Other control vendors permit royalty-free redistribution of the runtime version of the control only, while charging for the developer license. Users should read the license agreement provided with the control to understand how they can distribute a control on the Web.
I cannot get some of the controls, including those that come with Visual Basic 4.0, to be displayed in Web pages using the Internet Explorer 3.0.
Many controls, such as those supplied with Visual Basic 4.0, implement licensing. To distribute these controls over the Web, you must generate the appropriate runtime license file and include it with your Web page; otherwise, the controls will not display on users’ machines. Only people with a valid developer license for a given control can generate a runtime license for that control. For detailed instructions on including runtime-licensed controls in your Web pages, see the ActiveX SDK documentation on licensed controls (there is also an example in the new ActiveX Control Pad FAQ). Note that Microsoft and third parties are also supplying many ActiveX controls for royalty-free runtime use on the Web. No runtime license file is necessary to include these controls in a Web page. Check the Internet Explorer controls page for details.
What controls are available today from Microsoft? Which controls are included with the ActiveX Control Pad and Internet Explorer 3.0?
To see a more complete list of available controls, visit the ActiveX Component Gallery on the Microsoft Web site. The following controls will ship with the Internet Explorer 3.0 final release (those marked with a * will be included in "typical" and "complete" installs of Internet Explorer 3.0):
Controls that ship with Internet Explorer 3.0 and the ActiveX Control Pad Controls that ship with Internet Explorer 3.0 and the ActiveX Control Pad (see the Internet Explorer page):
(see the Internet Explorer page):Control Name Description
Controls that ship with Internet Explorer (Minimum, Typical and Complete installs)
Web Browser Control A Web browser control (based on Internet Explorer 3.0) that can display HTML pages and ActiveX controls and ActiveX documents.
Timer Can be programmed to execute actions/scripts at set time intervals.
Marquee control Scrolls any HTML file in either a horizontal or vertical direction and can be configured to change the amount and delay of scrolling. This control is built in to Internet Explorer.
Controls that ship with Internet Explorer 3.0 (Complete install)
ActiveMovie Control
Displays streaming and non-streaming media, such as video, sound, and synchronized images w/ sound.Controls that ship with Internet Explorer 3.0 (Complete install) and with the ActiveX Control Pad
The HTML Layout Control Displays 2-D HTML regions inside Internet Explorer 3.0 using new World Wide Web Consortium (W3C) extensions to HTML.
Microsoft Forms 2.0 Label Used for creating basic text labels.
Microsoft Forms 2.0 Textbox A multiline text-entry and text-display window.
Microsoft Forms 2.0 Combo Box Allows users to choose from a drop-down list of options.
Microsoft Forms 2.0 List Box Allows users to choose from a scrollable list of options.
Microsoft Forms 2.0 CheckBox Allows user to check an option.
Microsoft Forms 2.0 Option Button Allows users to choose between multiple options.
Microsoft Forms 2.0 Toggle Button A button that has a toggle state (for example, on/off).
Microsoft Forms 2.0 Command Button A basic pushbutton control.
Microsoft Forms 2.0 Tabstrip Provides multiple pages that can be selected via tabs.
Microsoft Forms 2.0 ScrollBar Basic horizontal and vertical scroll bars.
Microsoft Forms 2.0 Spin Button A button that can be pushed up or down.
The Microsoft ActiveX Image Control Displays progressively rendered images in metafile, .JPG, .GIF, .BMP, or wavelet formats.
The Microsoft ActiveX Hotspot Control Used to add a transparent hotspot within the HTML Layout Control.
Microsoft controls available seperately in the ActiveX Component Gallery Web site
Animated Button
Displays various frame sequences of an .AVI depending on the button state. It uses the Windows Animation Common Control. The .AVI file must be RLE compressed or 8-bit compressed.Chart
Enables you to draw various types of charts with different styles.Gradient
Shades the area with range of colors, making transition from a specified color to another specified color.Label
Displays given text at any specified angle. It can also render the text along user defined curves. It supports Click, Change, MouseDown, MouseOver, MouseUp events.Menu
Allows the Web author to place a menu button on the page that brings up a menu using the standard menu look and feel. The menu control fires events that the author can respond to via VBScript code.Popup Menu
Displays a pop-up menu whenever the method PopUp is called. This control fires an event when a menu item is clicked.Popup Window
Displays specified HTML documents in a pop-up window. This control can be used to provide tooltips or preview links.Preloader
Downloads the file at the specified URL and puts it in the cache. The control is invisible at runtime and starts downloading when enabled. When the download is finished, the control fires a Complete event.Stock Ticker
Displays changing data continuously by downloading the specified URL at regular intervals and displaying that data. The data can be in a text or .XRT format.View Tracker
Generates a set of events whenever the controls enters or leaves the viewing area. The author can use this control to automatically modify properties or functionality on the page based on sectional input.Note that other controls will be made available on an ongoing basis from Microsoft and third parties. Many are available in the ActiveX Component Gallery Web site at http://www.microsoft.com/activex/gallery.
Which ActiveX controls are available today from third-party software vendors?
More than 1,000 controls are commercially available from third-party software vendors. See the ActiveX Component Gallery for a list of companies developing Internet-enhanced ActiveX controls.
Once I install these controls, how can I develop ActiveX Web pages that use them?
Use the ActiveX Control Pad to insert these controls into your HTML Web pages. Follow the ActiveX Control Pad tutorial to learn how to use this tool. (See the ActiveX Control Pad pages on this Web site.)
How does the HTML Layout Control enhance my ability to create pages using ActiveX controls?
The HTML Layout Control supports new HTML extensions published by W3C that allow objects to be positioned exactly on a Web page. Previously, HTML did not allow Web developers to exactly position elements on a page using specific x,y coordinates, and did not allow overlapping objects. These "2-D" layout capabilities help developers create more sophisticated designs and Web applications for their users. By implementing these new W3C HTML extensions, the HTML Layout Control provides advanced layout options for ActiveX controls displayed in Internet Explorer 3.0. The HTML Layout Control is an add-on for Internet Explorer 3.0 and is integrated into the Internet Explorer 3.0 "Complete" install. (The HTML Layout Control is also part of the ActiveX Control Pad, and available for separate/automatic download from the Web. The ActiveX Control Pad can be used in conjunction with the HTML Layout Control, since it provides a full frame-based WYSIWYG page editor that makes it easy to create advanced, 2-D-style HTML designs using ActiveX controls.
