I know how to use ajax for submitting a form and all. What I am concerned about is, what is actually happening in the background when a form is submitted via ajax.
How are the values transferred? Encrypted or not? And what is the need of specifying submission type, I mean get or post, if the URL is not showing the form fields?
Edit: Found this on w3schools:
GET requests can be cached
GET requests remain in the browser history
GET requests can be bookmarked
GET requests should never be used when dealing with sensitive data
GET requests have length restrictions
GET requests should be used only to retrieve data
POST requests are never cached
How do these apply to ajax form submission?
Basically, when you Ajax-submit a form, it is doing exact same thing as what would happen when you as a user GET or POST submit a form - except that it is done in an asynchronous thread by the browser - i.e. called XMLHttpRequest.
If you submit form as a GET request, all of the form values are stitched together as parameter strings and appended to the URL (form's ACTION URL) - prefixed by a ?. This means anyone who can intercept that communication can read the submitted form data even if request is sent to a HTTPS URL. The POST method sends form data as a separate block (from the URL) and if URL is HTTPS then form data gets encrypted.
It looks like you are just starting out in the world of web development - welcome to the world of programming. I would recommend reading up on some good web development/programming books (I don't want to promote any particular book here). Amazon may help suggest few good ones under "Web Development" kind of search terms.
Also, I suggest that you read up a little on GET vs. POST by googling for it (I can only include one or two links - google will show you hundreds).