tailieunhanh - JavaScript Bible, Gold Edition part 129

JavaScript Bible, Gold Edition part 129. 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. | 1128 Part IV JavaScript Core Language Reference Global functions are not tied to the document object model. Instead they typically enable you to convert data from one type to another type. The list of global statements is short but a couple of them appear extensively in your scripting. Functions decodeURIC encodedURI decodeURIComponentC encodedURIComponent encodeURI URIString encodeURIComponentCURIComponentString Returns String. NN2 NN3 NN4 NN6 IE3 J1 IE3 J2 IE4 IE5 Compatibility The ECMA-262 Edition 3 standard as implemented in and NN6 provides utility functions that perform a more rigorous conversion of strings to valid URI strings and vice versa than was achieved earlier via the escape and unescape functions described later in this chapter . The purpose of the encoding functions is to convert any string to a version that you can use as a Uniform Resource Identifier such as a Web page address or an invocation of a server CGI script. While Latin alphanumeric characters pass through the encoding process untouched you must use the encoding functions to convert some symbols and other Unicode characters to a form hexadecimal representations of the character numbers that the Internet can pass from place to place. The space character for example must be encoded to its hex version 20. Perhaps the biggest difference between the encodeURI and escape functions and their decodeURI and unescape counterparts is that the more modern versions do not encode a wide range of symbols that are perfectly acceptable as URI characters according to the syntax recommended in RFC2396 http rfc . Thus the following characters are not encoded via the encodeURI function @ - _ . Use the encodeURI and decodeURI functions only on complete URIs. Applicable URIs can be relative or absolute but these two functions are wired especially so symbols that are part of the protocol search string and for instance and directory level delimiters are not encoded. The .