December 8, 1999 - HTML Applications (HTAs) | WebReference

December 8, 1999 - HTML Applications (HTAs)

Yehuda Shiran December 8, 1999
HTML Applications (HTAs)
Tips: December 1999

Yehuda Shiran, Ph.D.
Doc JavaScript

HTML Applications (HTAs) behave like any other applications on your computer, whether they are written in C++, Visual Basic, or J++. HTAs are like a dream come true for programmers who want the power of Internet Explorer without its strict security model and user interface. Now you can create browser-dependent applications that display themselves to your users as a plain window, without any resemblance to Internet Explorer's window. Your application needs to define the user interface, all by itself.

For authors of browser-based Applications, you may find HTAs attractive as they hide the fact that they were written in HTML, DHTML, and JavaScript. For those of you that haven't tried yet writing applications for the Web, HTAs may be the turning point, at they are easier to write than C++ or Java applications. Programmers that write applications for the PC may consider writing them as HTAs now. You get the power of the DHTML & JavaScript languages and avoid the security shortcomings of Internet Explorer.

An HTA file looks exactly like an HTML file. The only thing that distinguishes it as an HTA file is its file extension: hta instead of html or htm. Here is the simplest HTA application:

Doc JavaScript's One-liner HTA

This is not a mistake. Both Internet Explorer and Netscape Navigator do not require the <HTML>, <BODY>, and <HEAD> tags. Click here to invoke this HTA. Like any other Windows applications, the browser asks you whether to save it to disk or to open it. Select to open it. Examine the application window for a moment. Its title is the HTA file name and its content area is what's included in the <BODY> tag. In this example, the one-liner above, Doc JavaScript's One-liner HTA, becomes the content of the <BODY> tag, by default.

Notice that the only way to close the application above is to click the x button at the window's top right corner. Normally, you would want to provide a more elegant exit from your application. Let's enhance the example above and add an exit button. Let's also be more formal and add the missing <HTML>, <BODY>, and <HEAD> tags:

<TITLE>Doc JavaScript's HTA (</TITLE>
This is Doc JavaScript's HTA<BR>
<BUTTON onclick="self.close()">Go Away</BUTTON>

Now launch the ATA and open this application when asked by the browser. Examine the application window. Notice that its title is no longer the HTA file name, but rather the <TITLE> of the page. Also notice the usage of JavaScript to handle the onclick event of the Go Away <BUTTON>. In this application, as opposed to the previous one, your user has a way to exit the window in a more elegant fashion.

Column39, HTML Applications describes in more details how to create and install HTML Applications.