tailieunhanh - JavaScript Bible, Gold Edition part 68

JavaScript Bible, Gold Edition part 68. 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. | 518 Part III Document Objects Reference start Value String Read Write NN2 NN3 NN4 NN6 IE3 J1 IE3 J2 IE4 IE5 Compatibility The start property works in conjunction with video clips viewed through the IMG element in IE4 . By default a clip starts playing except on the Macintosh when the image file opens. This follows the default setting of the start property fileopen . Another recognized value is mouseover which prevents the clip from running until the user rolls the mouse pointer atop the image. On the Example on the CD-ROM CD-ROM r Related Items properties. useMap Value Identifier String Read Write NN2 NN3 NN4 NN6 IE3 J1 IE3 J2 IE4 IE5 Compatibility The useMap property represents the USEMAP attribute of an IMG element pointing to the name assigned to the AREA element in the page see Listing 22-7 on CD-ROM . This AREA element contains the details about the client-side image map described later in this chapter . The value for the useMap property must include the hash mark that defines an internal HTML reference on the page. If you need to switch among two or more image maps for the same IMG element for example you swap images or the user is in a different mode you can define multiple MAP elements each with a different name. Then change the value of the useMap property for the IMG element object to associate a different map with the image. Related Item isMap property. vspace See hspace. width See height. Chapter 22 Image Area and Map Objects 519 X y Value Integer Read-Only NN2 NN3 NN4 NN6 IE3 J1 IE3 J2 IE4 IE5 Compatibility An NN4 script can retrieve the x and y coordinates of an IMG element the top-left corner of the rectangular space occupied by the image via the x and y properties. These properties are read-only. They were supplanted in NN6 via the offsetLeft and offsetTop properties of any element. Even without Dynamic HTML you can use the information from these properties to help scroll a NN4 document to a precise .