Like conventional data submission Ajax data submit also of two types, GET and POST. There relative merits demerits are same as conventional data submission.
How data is submitted using Ajax
2. This function establishes connection with the server by XML HTTP REQUEST object. When connection is established data from the form fields are transmitted to the server.
Advantages and disadvantages
1. As whole page is not reloaded Ajax submission is faster than conventional form submission process.
2. It is more user friendly.
3. Use of Ajax is not limited to form data submission. It is widely used in dynamic menu design; collecting data for web stat analysis, or even reload the entire page dynamically.
5. As data are dynamically loaded web history is not available, ie you can not reload page by using back button of your browser.