How can I get form data with JavaScript/jQuery?

Question

Is there a simple, one-line way to get the data of a form as it would be if it was to be submitted in the classic HTML-only way?

For example:

Answer 1

Here's a really simple and short soluton that even doesn't require Jquery.

var formElements=document.getElementById("myForm").elements;    
var postData={};
for (var i=0; i