Tham khảo sách 'javascript bible_ chapter 44', công nghệ thông tin, kỹ thuật lập trình phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Internet Explorer 4 JScript and Object Model Diversity is often a good thing. But when you are trying to develop scripted Web applications that work on all browsers diversity can become a hurdle to overcome. That s the case when authors learn scripting in one browser environment only to discover too late that some object property method or event is not supported or is supported differently in the other browser. By including JavaScript in the title of this book I signal that the focus of the book is Netscape s implementation of the language in Navigator. But I cannot ignore Internet Explorer and its JScript language which is derived from JavaScript. The purpose of this chapter is not to teach you everything you need to know about scripting in JScript for Internet Explorer-only applications. Instead I want to provide an overview of the pieces in Internet Explorer 4 that differ. Some of what you read about here may eventually come to Navigator in a future version. Core Language Internet Explorer s internal architecture clearly distinguishes the core scripting language from the document object model. This is necessary in Internet Explorer because the browser supports two scripting languages VBScript and JScript. While it is unlikely that a document would contain scripts in both languages nothing prevents such a situation. Each SCRIPT tag set can be assigned a different language name in the LANGUAGE attribute and the interpreter of only the named language is invoked for the script. In This Chapter Internet Explorer 4 s object containment structure The wide range of Internet Explorer 4 element objects How to determine the version of JScript installed in the browser 908 Part IV Putting JavaScript to Work The core language consists of the normal kinds of programming constructs how variables work conditional constructions data types and similar items that any programming language needs regardless of the object environment. Microsoft Netscape and other participants .
