why in $.ajax() does not work success: function(html)(document.getElementById)!?

Hello
In this code, $.ajax function worked , but success: function(html) does not work(document.getElementById).

I do not know why it does not work!? What do I do?

$(".submit").click(function(){    
        var entry_id = $("#entry_id").val();
        var comment_body = $("#comment_body").val();
        var comment_name = $("#comment_name").val();
        var comment_email = $("#comment_email").val();
        var comment_url = $("#comment_url").val();
        var dataString = 'entry_id=' + entry_id + '&comment_body=' + comment_body + '&comment_name=' + comment_name + '&comment_email=' + comment_email + '&comment_url=' + comment_url;
        
        if (comment_body == '' || comment_name == '' || comment_email == '' || comment_url == '') {
            alert('Please Give Valide Details');
        }
        else {
            $("#flash").show();
            $("#flash").fadeIn(400).html('<span class="loading">&#1604;&#1591;&#1601;&#1575; &#1605;&#1606;&#1578;&#1592;&#1585; &#1576;&#1605;&#1575;&#1606;&#1740;&#1583;...</span>');
            $.ajax({
                type: "POST",
                url: "/zig-co/blog/comment_insert",
                data: dataString,
                cache: false,
                success: function(html){                                    
                    var s1 = document.getElementById('comment_body');
                    var s2 = document.getElementById('comment_name');
                    var s3 = document.getElementById('comment_email');
                    var s4 = document.getElementById('comment_url');
                    $("#update").append(html);
                    $("#update li:last").fadeIn("slow");
                      s1.value + s2.value + s3.value + s4.value;                  
                    $("#name").focus();
                    
                    $("#flash").hide();
                }
            });
        }
        return false;
    });

After looking at your code i can safely say that just adding the values together isn’t going to work as your not storing the value anywhere. Also I’m interested to know why your using native JS and not jQuery to retrieve the values.

Thank!
I want after send a message, that message submit online and insert to database, Without Refresh Page…
For example: Comments with jQuery and Ajax

Please tell an example?

Is there a working demo of your page as feeding examples isn’t the best idea when it comes to AJAX.

What is your suggestion? What should I do for this work with jQuery?

Do is document.getElementById for jQuery?
the for show’s value input ($ _POST) as online and without Refresh Page, What do i do?