Jquery Hover无法正常工作

Question

我在下面有以下脚本。我从php（JSON编码）获取数据。当我悬停鼠标时，我试图改变块的颜色，但它不起作用。任何的想法 ？

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
    <script>
    $(document).ready(function(e) {
        //
        $(".comment-block").mouseenter(function(){
            $(".comment-block").css("background-color", "yellow");
        });
         $(".comment-block").mouseout(function(){
            $(".comment-block").css("background-color", "lightgray");
        });
        //Show Initial Data
        $.ajax({
            type: "get",
            url:"main_board.php",
            cache: false,
            data: { get_param : "value" },
            dataType:"json",
            success:function(data) {
                $.each(data, function(index, element) {
                    var final_data = "<div class='comment-block'>" + "<div class ='comment-item'>" + "<div class ='comment-avatar'>" + "<img src='avtar.png' alt= 'avatar'></div>" + "<div class='comment-post'>" +"<h3>" + element.UserName + "<span></h3><p>" + element.Messages + "</p></div></div>";
                    $("#php").append($(final_data).hide().fadeIn());
                    }); 
                }
            }); 

    });
    </script>