how to call ajax in javascript on click of button code example

Example: ajax exmaple\

$.ajax({
    url:'your url',
    type: 'POST',  // http method
    data: { myData: 'This is my data.' },  // data to submit
    success: function (data, status, xhr) { // after success your get data
        $('p').append('status: ' + status + ', data: ' + data);
    },
    error: function (jqXhr, textStatus, errorMessage) { // if any error come then 
            $('p').append('Error' + errorMessage);
    }
});