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1 <script type="text/javascript" src="json2.js">
<script type="text/javascript">
var jsonString = '{"name":"Joe Shmoe", "phone":"415-111-1111"}';
var employee=JSON.parse(jsonString);
alert("Name: " + + "\nPhone: "+;
The JavaScript program will use the json2.js library.
A string is created containing the text that will be parsed by the library's
JSON.parse() method.
The JSON.parse() method converts the string, called jsonString, into a JavaScript
object (see Figure 18.23).
Figure 18.23 After adding the json2.js library, Internet Explorer works fine.
Douglas Crockford at has provided a set of routines that will convert any
JavaScript data type into a JSON string. Go to for a free
download of the most current library for parsing and stringifying JSON objects, json2.js .
With this library you can read JSON strings and write them to the server. Example 18.24
demonstrates how to use the json2.js library to create a JavaScript object from the text
coming from the JSON file.
The steps are:
1. Make sure the .json file is in the correct object format. (The MIME type is
“application/json” and may have to be set in your server so that Firefox does
not read the JSON file as an XML file resulting in a “not well-formed” error.)
2. At the top of your Ajax program add the <script> tag src attribute to the name of
the JSON library, in this case “json2.js”:
<script type="text/javascript" src="json2.js">
3. In the Ajax program, read the object in as text from the XMLHttpRequest object's
responseText property into a string variable.
4. Use the JSON.parse() method to turn the string into a JavaScript object.
5. Use the properties and values of the object to get the information from the
object such as , , and so on.
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