JSON stands for JavaScript Object Notation. It is a format for storing and exchanging data. It is based on a subset of the JavaScript Programming Language.

The file type for JSON files is “.json” and MIME type for JSON text is “application/json“.

Here are the characteristics of JSON:

1. It is a lightweight data-interchange format.
2. It is easy for humans to understand.
3. It uses Javascript format but it is a text which makes it is completly language independent as text can be read and parsed by any programmng language.

While working with AJAX in Magento many of you might have received the following error like I did:

2013-05-02T10:25:15+00:00 DEBUG (7): HEADERS ALREADY SENT:
[0] /var/www/html/ecomm/app/code/core/Mage/Core/Controller/Response/Http.php:44
[1] /var/www/html/ecomm/lib/Zend/Controller/Response/Abstract.php:727
[2] /var/www/html/ecomm/app/code/core/Mage/Core/Controller/Response/Http.php:75
[3] /var/www/html/ecomm/app/code/core/Mage/Core/Controller/Varien/Front.php:188
[4] /var/www/html/ecomm/app/code/core/Mage/Core/Model/App.php:304
[5] /var/www/html/ecomm/app/Mage.php:599
[6] /var/www/html/ecomm/index.php:104