Jquery and HTML FormData returns "Uncaught TypeError: Illegal invocation"

Adding processData: false to the $.ajax options will fix this issue.

jQuery processes the data attribute and converts the values into strings.

Adding processData: false to your options object fixes the error, but I'm not sure if it fixes the problem.

Demo: http://jsfiddle.net/eHmSr/1/

My experience:

  var text = $('#myInputField');  
  var myObj = {title: 'Some title', content: text};  
  $.post(myUrl, myObj, callback);

The problem is that I forgot to add .val() to the end of $('#myInputField'); this action makes me waste time trying to figure out what was wrong, causing Illegal Invocation Error, since $('#myInputField') was in a different file than that system pointed out incorrect code. Hope this answer help fellows in the same mistake to avoid to loose time.

I had the same problem

I fixed that by using two options

contentType: false
processData: false

Actually I Added these two command to my $.ajax({}) function