Hypertext Markup Language (HTML) 4.01 and Javascript 1.5., used with Internet Explorer 5.5, Netscape 6.0, or later, are discussed in this book. This Java has no relationship to the Java programming language, except in name. “Script” indicates that this software, which works within an Internet browser, is interpreted, not compiled. Javascript provides for dynamic HTML. It is derived from the computer languages C and Perl; Algol is a distant ancestor. JavaScript is object-based, and is not a structured, object-oriented language.
The text groups related subjects together, by chapter. Each object element tag is listed, along with its background, a table listing its properties, and a table of its methods. The author starts simply, with a description of how Javascript writes output to HTML, and continues on through a discussion of complexity of objects. Each subject is illustrated with a working, annotated example, including output screen images. Frequently, the list of items to be covered is large enough that only a brief sample of properties and methods are used in the HTML-Javascript example. Where there are differences between Netscape’s and Internet Explorer’s renderings, both screen images are included, with discussion.
The book could be used as a classroom text, as the CD-ROM that comes with the book contains lab work. Each of the HTML-Javascript examples in the book is also available on the CD-ROM. The examples demonstrate what works, including how to write the supporting HTML and Javascript code.
The book also includes many universal resource locators (URLs), scattered throughout the text and in Appendix A, which provide pointers to where you can find Javascript programs to add to your collection. Appendix B is a review of basic HTML, and Appendix C is an introduction to common gateway interface (CGI) Perl. The Perl specifically shows example server code for processing HTML inquiries and forms. All the examples on the CD-ROM were developed and tested by the author using Internet Explorer 6.0 and Netscape 7.0. The book and CD-ROM appear to have been written and published in haste; there are typographical errors sprinkled throughout.
As part of my review of the book and CD-ROM, I examined the included code. Here is what I found. When the HTML examples were tested using Internet Explorer 5.0, most worked fine. Those that required a later version of the browser had HTML-Javascript errors. Installing Internet Explorer 6.0 fixed most of these problems, but there are at least three HTML examples in the book designed to run specifically on the Netscape browser. HTML that required a browser that was Internet Explorer 5.5 or later produced errors like “is not an object,” “object missing,” or “object expected.” Occasionally, there were HTML examples or graphics missing from the CD-ROM. I replaced these with mockups to force the code to run.
The HTML in the book was checked using output screen captures. Some screen captures were missing. Sometimes, there was a mismatch between the HTML and the screen image. Occasionally, there was a mismatch between the HTML listing in the book, and that on the CD-ROM. Some HTML had errors because of word-wrap issues and missing quotes. (Once that was fixed, these examples ran fine.) A couple of examples required Web access to run, since they included links. This was not necessary to demonstrate the concepts being described. I fixed these by editing the file locally, capturing the screen as a .jpg or .gif file, and adding a local HTML Web page to display the graphic. One may want to do this in a classroom lab situation.
There are typographical errors scattered throughout the book, for example between an HTML code fragment and its corresponding discussion. Otherwise, the book is well organized and presented. The text could also have been improved by the use of standard naming conventions to relate frames to parent examples. The code in Example 12.6, for example, could be identified as parent to the code in Example12.6LF (left frame) and 12.6RF (right frame). In the text, the frame parts should be clearly labeled, with a border and naming as the first line comment: “File: example-12.6LF left frame”. This would eliminate confusion found in the book and on the CD-ROM. The CD-ROM should also have an index arranged alphabetically by topic, in addition to the index by number, to facilitate its use as a reference.
The underlying concept of the book is good. It is too bad that the CD-ROM is not clean enough to be immediately usable in a classroom, without work to fix it first. It would be useful to have a new edition of this book and the CD-ROM before a revision is needed for the Javascript 1.6 release.
