jQuery AJAX Snippet

ajax.js

$.ajax({
    url: 'api/url',
    method: 'POST',
    data: {var:'val'},
    contentType: "application/json; charset=utf-8",
    dataType: 'json'
}).done(function(data, textStatus, jqXHR) {
    console.log('done');
}).fail(function(jqXHR, textStatus, errorThrown) {
    if (jqXHR.responseJSON) {
        console.log('failed with json data');
    } else {
        console.log('failed with unknown data'); 
    }
});