With the still-rising popularity of web services, XML has practically become the de facto standard for data transmission. However, XML is not without its detractors. For example, some consider it to be overly verbose for data transmission purposes, necessitating many more bytes of information to be sent across the Internet to accomplish what could have been done in a much smaller form. To take this into consideration, new forms of XML compression and even entire new XML formats, such as Binary XML, have been developed. All these solutions work on extending or adding on to XML, making backwards compatibility an issue. Douglas Crockford, a long-time software engineer, proposed a new data format built on JavaScript called JavaScript Object Notation (JSON).
Up until this point, you've used either plain text or XML to transmit data back and forth to the server. This chapter introduces the use of JSON in Ajax communication as an alternative to these more traditional data formats.