JSON vs XML

Both JSON and XML can be used to receive data from a web server.

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The following JSON and XML examples both defines an employees object, with an array of 3 employees:

JSON Example

{"employees":[
    { "firstName":"John", "lastName":"Doe" },
    { "firstName":"Anna", "lastName":"Smith" },
    { "firstName":"Peter", "lastName":"Jones" }
]}

XML Example

<employees>
    <employee>
        <firstName>John</firstName> <lastName>Doe</lastName>
    </employee>
    <employee>
        <firstName>Anna</firstName> <lastName>Smith</lastName>
    </employee>
    <employee>
        <firstName>Peter</firstName> <lastName>Jones</lastName>
    </employee>
</employees>

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 JSON is Like XML Because

• Both JSON and XML are "self describing" (human readable)
• Both JSON and XML are hierarchical (values within values)
• Both JSON and XML can be parsed and used by lots of programming languages
• Both JSON and XML can be fetched with an XMLHttpRequest

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JSON is Unlike XML Because

• JSON doesn't use end tag
• JSON is shorter
• JSON is quicker to read and write
• JSON can use arrays

The biggest difference is:
 XML has to be parsed with an XML parser. JSON can be parsed by a standard JavaScript function.

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Why JSON is Better Than XML

XML is much more difficult to parse than JSON.
JSON is parsed into a ready-to-use JavaScript object.

For AJAX applications, JSON is faster and easier than XML:
Using XML

• Fetch an XML document
• Use the XML DOM to loop through the document
• Extract values and store in variables

Using JSON

• Fetch a JSON string
• JSON.Parse the JSON string

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