tailieunhanh - JavaScript Bible, Gold Edition part 8

JavaScript Bible, Gold Edition part 8. This book will bring programmers and non-technical professionals, including casual programmers and scripters, painlessly up to speed on all aspects of mastering JavaScript. Key topics include programming fundamentals, JavaScript language elements and how to use them effectively, and how to easily and efficiently add powerful new functionality to HTML documents and Java applets. | 34 Part II JavaScript Tutorial Summary can grab a snapshot of the date and time of the client s system clock or create a date object for dates in the past or future. Want to display on your page how many shopping days remain until next Christmas That s one application for Date object calculations. Chapter 11. Scripting Frames and Multiple Windows One of the strengths of a scriptable browser is that scripts facilitate the management of multiple frames far better than server-based applications. For example you can script a link in one frame of a three-frame window to change the documents loaded into the other two frames. Or you can use one static frame to preserve accumulated data from pages that come and go from one of the other frames. The trickiest part of managing frames is knowing how script statements refer to other frames and elements in those other frames. In this chapter you learn the three possible relationships among a parent that is the framesetting document and two or more child frames. Depending on which document contains the script and which document contains the element to reference the format of the reference needs to be assembled properly. Some of the same techniques apply to managing multiple windows. Not only are multiple windows more difficult to manage from a user interface point of view scripting them also presents several challenges. In this lesson you begin to appreciate the issues involved. Chapter 12. Images and Dynamic HTML In the final chapter of the tutorial you travel beyond the confines of the lowest common denominator to embrace concepts that work with a lot of browsers and can greatly improve the user experience on your page. At the core is the image object. The image object has a split personality. On one side is the object represented in a page by its IMG tag on the other side is an image object in memory that allows scripts to preload images invisibly into the browser s memory cache. Through these two mechanisms scripts can .