The origin of JSON
XML is used to format data. Is there any better way if we don't need XML? The answer is JSON. Before introducing JSON, let me first introduce javasThis script language. The scripting language has its own talent for dynamic execution. That is, we can put the statement we want to execute in the string, through EVThe dynamic execution function al_r () is used for execution. The content in the string will be executed like the script we wrote.
Example 1:
<HTML>
<Head>
<Title> EVAl Example 1 </title>
</Head>
<Body>
<SCRIPT>
STR = "alert ('hello ')";
EVAl_r (STR );
</SCRIPT>
</Body>
</Html>
The Hello window is displayed.
We can put any script statement in the string, including the declaration statement:
<HTML>
<Head>
<Title> EVAl Example 2 </title>
</Head>
<Body>
<SCRIPT>
Define = "{Name: 'Michael ', email: '17bity @ gmail.com '}";
EVAl_r ("daTa = "+ define );
Alert ("name:" + DATa. Name );
Alert ("Email:" + DATa. Email );
</SCRIPT>
</Body>
</Html>
If the asynchronous text in the background is javasThe statement of declare, so it is not an EVCan the Al method be parsed? How efficient is this process for parsing complex XML!
Now let's tell you what JSON is: javasJsonobject notation. I prefer to translate it into javasStatement object declaration. For example, to load some address book information from the background, if it is written as XML, as follows:
<Contact>
<Friend>
<Name> Michael </Name>
<Email> 17bity@gmail.com </Email>
<Homepage> http://www.jialing.net </Friend>
<Friend>
<Name> JOHN </Name>
<Email> john@gmail.com </Email>
<Homepage> http://www.john.com </Friend>
<Friend>
<Name> Peggy </Name>
<Email> peggy@gmail.com </Email>
<Homepage> http://www.peggy.com </Friend>
</Contact>
In JSON format:
[
{
Name: "Michael ",
Email: 17bity@gmail.com ",
Homepage: "http://www.jialing.net"
},
{
Name: "John ",
Email: john@gmail.com ",
Homepage: "http://www.jobn.com"
},
{
Name: "Peggy ",
Email: peggy@gmail.com ",
Homepage: "http://www.peggy.com"
}
]
The simplest is not just expression, but the most important thing is to discard the confusing Dom parsing. BecauseThe statement specification of the statement, the statement Crip will automatically help you resolve. The basic method to use JSON in Ajax is to load the background declaration javas on the foreground.The string of the sequence object, using EVTo convert it to the actual object, and then update the page information through DHTML.
JSON format
The basic JSON format is as follows:
? An object is a set of attributes and value pairs. An object starts with "{" and ends "}". Each attribute name and value is separated by a ":" prompt, and.
? An array is a set of ordered values. An array starts with "[", ends with "]", and values are separated. ? The value can be a string, number, true, false, or null in quotation marks, or an object or array. These structures can be nested. ? The definition of a string is basically the same as that of C or Java .? The definition of numbers is also basically the same as that of C or Java.
JSON XML
? Readability
The readability of JSON and XML is comparable. One side is the suggested syntax and the other side is the standard tag format, which makes it difficult to distinguish between the two.
? Scalability
XML is inherently highly scalable, and JSON is also available. There is nothing XML can be extended, and JSON cannot.
? Encoding difficulty
XML has rich coding tools, such as dom4j and JDOM, and JSON also provides tools provided by json.org. However, JSON encoding is much easier than XML, JSON code can be written without tools, but it is not easy to write XML.
? Decoding difficulty
XML parsing takes into account the parent node of the child node, which is confusing, and the difficulty of JSON Parsing is almost 0. There is nothing to say about XML.
? Popularity
XML has been widely used in the industry, and JSON is just the beginning. However, in the specific field of Ajax, the future development of XML must be in JSON. Then Ajax should become ajaj (asynchronous javasBytesAnd JSON.
# JavasExamples/ajax Columns
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