将ajax转换为json

This is normal form submission to codeigniter framework. This is a ajax form submission. How to convert this to jason and send to below URL?

data: 'question=' + question + '&idquestion_table=' + idquestion_table + '&answer_1=' + answer_1 + '&answer_2=' + answer_2 + '&answer_3=' + answer_3 + '&answer_4=' + answer_4 + '&correct_answer=' + correct_answer + '&category=' + category,
                                url: "<?php echo base_url('index.php/admin_question_controller'); ?>",
                                type: 'put',

Hopefully my code can help you to deal with your issue

<html>
    <input type="button" value="button" id="ID1" />
</html>
<script>
     $("#ID1").click(function () {
            var user = {
                username:'***@gmail.com',
                password:'!aA1234'
            };
        $.ajax({
            type: 'POST',
            url: 'http://***/index.php',          
            data: user,          
            datatype: "json",
            error: function (XMLHttpRequest, textStatus, errorThrown) {  
                alert(textStatus);
            },
            success: function (data) {
             alert(data)
            }
        });
    });
</script>