JSON verification in JQUERY

Question

I have an ajax chat on my website. However, sometimes messages are duplicated for reasons not relevant. Therefore, I would like to check if the messages I receive in JSON already exist in the chat, if they exist, do not show them and if they do not exist, show them. The code I have is:

var VerificaChat = function(TempoRequest){
						$.ajax({
							url: 'chat_receive.php',
							dataType: 'JSON',
							type: 'POST',
							data: 'type=recebeMsg&lobby=' + $('.lobbyid').val(),
							success: function(data){
								if(data.status === 'success'){
									
										for( var i = 0; i < data.msgs; i++){
											if(data[i]['time'] !== 'ambos'){
                      // AQUI EU GOSTARIA DE VERIFICAR AS MENSAGENS MOSTRADAS NO CHAT, E VER SE A MENSAGEM RECEBIDA NO JSON É IGUAL A QUE APARECE NA TELA DO USUÁRIO.
                      //ABAIXO EU MONTO A MENSAGEM E MOSTRO AOS USUÁRIOS.
                      
                     
											$('#chat_box').append('<div class="msg user_' + data[i]['time'] + '"><span>'+ data[i]['nick'] + ': </span>' + data[i]['contente'] +'</div)');	
                      
                      
                      
											}else{
                      
											$('#chat_box').append('<div class="msg ambos"><span>'+ data[i]['nick'] + ' </span>' + data[i]['contente'] +'</div)');	
											}
										}

              });
							
				}

<div id="chat_box">

<!--EXEMPLO DE MENSAGEM-->
<div class="msg user_azul"><span>VÍTOR:</span> Oi pessoal</div>

</div>

AJAX has the following JSON return (the return varies according to the number of new messages):

{  
   "0":{  
      "id_user":"10",
      "contente":"45454545454",
      "time":"azul",
      "nick":"ikeda."
   },
   "1":{  
      "id_user":"10",
      "contente":"4",
      "time":"azul",
      "nick":"ikeda."
   },
   "2":{  
      "id_user":"10",
      "contente":"5",
      "time":"azul",
      "nick":"ikeda."
   },
   "3":{  
      "id_user":"10",
      "contente":"45",
      "time":"azul",
      "nick":"ikeda."
   },
   "4":{  
      "id_user":"10",
      "contente":"44",
      "time":"azul",
      "nick":"ikeda."
   },
   "status":"success",
   "msgs":5
}