Use jQuery to update a field for a specific user


I need to update a field using jQuery and the API once the user clicks a link.

If I'm not wrong, I need a PUT request.

The user ID is 55ad2633a4520e471178f803,  so I tried the following: 

// PUT
$('.button').click(function(event) {
	var data = { 
	    field_41: ["55a1b550b2847881712431fe"]
	$.ajax( {
             // im almost sure my error comes from the url
	     url: '', 
	    type: "PUT", 
	        headers: {
	            "X-Knack-Application-Id": "556de6547d722ec119a0b534", 
	    data: data, 
	    success: function(response) { 
	        alert('Record Added!');

 In the Console, the error returned is: 

// [Error] Failed to load resource: the server responded with a status of 400 (Bad Request)

How is my URL supposed to be formated?


Thank you millions!

Remove the Content-Type header and it should work OK