javascript - Select every div inside another div and check it's class with jQuery -

i have chat system , i'm showing messages using jquery + json + php. problem is: have select each div inside div "#chatmessages", contains messages, , check it's class see if exists, ajax code:

    var data = {}; $.ajax({     type: "get",     datatype: "json",     url: "../room/a.php",     async: true,     cache: false,     data: data,     success: function(response) {         if(response.error) {             alert(response.msg);         } else {             for(var = 0; < response.length; ++) {                 if($("#chatscreen > *").hasclass("message" + i) == false)                 $("#chatscreen").append($("<div>",{                     class : 'message' + response[i][1],                     html  : response[i][0] + ' ' + response[i][4]                 }));             }         }     },     error: function (response) {          },     complete: function () {          }     }); 

response[i][0] contains name, , response[i][4] contains message. it's working fine, load function every 3000ms, repeat every message, how can check div per div searching class 'message' + response[i][1] (that contains unique id mysql)?

i tried use ".hasclass()" doesn't work.

if want know if there's element in div given class, can do:

if ($("#chatscreen").find(".message"+response[i][1]).length > 0) { 

you can refactor don't have search #chatscreen every time through loop:

var chatscreen = $("#chatscreen"); for(var = 0; < response.length; ++) {     if(chatscreen.find(".message"+response[i][1]).length > 0) {         chatscreen.append($("<div>",{             class : 'message' + response[i][1],             html  : response[i][0] + ' ' + response[i][4]         }));     } }