ajax click

$(".submit").click(function(){
    var datatime=$("#datatime").val();
    
    $.ajax({
        type:"POST",url: "http://www.demo.com/demo.PHP",data: "datatime="+datatime,dataType: "json",beforeSend: function(){
            $(".update_data").empty();
            $(".update_data").html("<img src=\'http://www.demo.com/imgs/wait.gif\' width=\'561\' height=\'160\' />");
        },success: function(data) {
            $(".update_data").empty();
           var mess = "处理完成，请关闭！";
            
           if(data.<span>Variable1</span> == data.<span>Variable2</span>){
               //write your code
            }else{<pre name="code" class="PHP">                //write your code
            }
        }
    });

});