tailieunhanh - Javascript bible_ Chapter 2

Tham khảo sách 'javascript bible_ chapter 2', công nghệ thông tin, kỹ thuật lập trình phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Authoring Challenges amid the Browser Wars If you are learning JavaScript just now in the brief history of scriptable browsers you have both a distinct advantage and disadvantage. The advantage is that you have the wonderful capabilities of the level 4 browser offerings from Netscape and Microsoft at your bidding. The disadvantage is that you have not experienced the painful history of authoring for older browser versions that were buggy and at times incompatible with each other due to a lack of standards. You have yet to learn the anguish of carefully devising a scripted application for the browser version you use only to have site visitors sending you voluminous e-mail messages about how the page triggers all kinds of script errors when run on a different browser brand generation or operating system platform. Welcome to the real world of scripting Web pages in JavaScript. Several dynamics are at work to help make an author s life difficult if the audience for the application uses more than a single type of browser. This chapter introduces you to these challenges before you type your first word of JavaScript code. My fear is that the subjects I raise may dissuade you from progressing further into JavaScript and its powers. But as a developer myself and as someone who has been using JavaScript since the earliest days of its public prerelease availability I dare not sugarcoat the issues facing scripters today. Instead I want to make sure you have an appreciation of what lies ahead to assist you in learning the language. I believe if you understand the Big Picture of the browser scripting world as it stands near the beginning of 1998 you will find it easier to target JavaScript usage in your Web application development. In This Chapter How leapfrogging browser developments hurt Web developers Why the core JavaScript language is separate from the document objects How to develop a cross-platform strategy 12 Part 1 Getting Started with JavaScript Leapfrog Browser .