1. JSON

2. Does Ajax need XML? The X in Ajax once stood for XML
Now x is more like ? Whatever that’s appropriate
XML has its advantages and disadvantages
Very expressive, but too noisy, large, slow…

3. JSON JavaScript Object Notation It is intended to be minimal
It is a textual notation of data
JavaScript is a superset of JSON
YAML is a superset of JSON
YAML decoder and JavaScript interpreter can be used as JSON decoder

4. Source: http:www/json.org
What’s in JSON
Source:

5. Source: http:www/json.org
String
Strings
Any double quoted Unicode character
Double quote escaped using \
Empty string represented by ""
Source:

6. Source: http:www/json.org
Number
Numbers
Integer, real, scientific
Use null for invalid/infinity
Source:

7. Source: http:www/json.org
Object
Objects: More of a hashmap notation
{"keyname": JSONValue, "keyname": JSONValue,…}
JSONValue may be any of the JSON value types including other objects
Source:

8. Source: http:www/json.org
Arrays
Arrays
Sequence of values
[JSONValue, JSONValue, JSONValue, …]
Index is decided by implementation (like Java can use 0, VB can use 1, JSON doesn’t care)
JSONValue may be any JSON value type including objects and arrays
Source:

9. Using JSON to Populate a Page

10. Concerns with eval
eval sends the JSON text (or any text) to the Java compiler
May not be safe
Use only if trusted source
What’s the alternative
parseJSON only parses JSON text

11. parseJSON Available from http://www.json.org/json.js
Parses only JSON text and is fast

12. Convert to JSON
toJSONString() converts an object to JSON

13. More Convenience More convenient processing functions are sprouting up
There is also proposal for JSONRequest object to be standardized by browsers