tailieunhanh - JavaScript Bible, Gold Edition part 74

JavaScript Bible, Gold Edition part 74. 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. | 578 Part III Document Objects Reference JavaScript is more forgiving about data types when assigning values to a text object. JavaScript does its best to convert a value to a string on its way to a text object display. Even Boolean values get converted to their string equivalents true or false. Scripts can place numeric values into fields without a hitch. But remember that if a script later retrieves these values from the text object they will come back as strings. About the only values that don t get converted are objects. They typically show up in text boxes as object or in some browsers a more descriptive label for the object. Storing arrays in a field requires special processing. You need to use the method to convert an array into a string. Each array entry is delimited by a character you establish in the method. Later you can use the method to turn this delimited string into an array. Example with Listings 25-2 and 25-3 on the CD-ROM Related Items defaultValue property. Methods blur Returns Nothing. NN2 NN3 NN4 NN6 IE3 J1 IE3 J2 IE4 IE5 Compatibility Just as a camera lens blurs when it goes out of focus a text object blurs when it loses focus when someone clicks or tabs out of the field. Under script control blur deselects whatever may be selected in the field and the text insertion pointer leaves the field. The pointer does not proceed to the next field in tabbing order as it does if you perform a blur by tabbing out of the field manually. Example on the CD-ROM On the CD-ROm Related Items focus method onBlur event handler. focus Returns Nothing. NN2 NN3 NN4 NN6 IE3 J1 IE3 J2 IE4 IE5 Compatibility Chapter 25 Text-Related Form Objects 579 For a text object having focus means that the text insertion pointer is flashing in that text object s field having focus means something different for buttons in a Windows environment . Giving a field focus is like opening it up for human .