SOURCE

var obj={"cmd":"messages.getMessages","flag":"","requestTime":"2018-10-12 14:25:52 +0800","requestData":"{\"dialogId\":\"C-167677-176215\",\"messageIdFrom\":110,\"messageIdTo\":130,\"maxCount\":-1}","responseTime":"2018-10-12 14:25:52 +0800","responseData":"{\"succ\":true,\"data\":{\"messages\":[{\"messageId\":129,\"type\":\"System\",\"dialogId\":\"C-167677-176215\",\"dialogKeyVer\":0,\"dialogKeyIter\":0,\"iv\":0,\"sender\":0,\"senderDevice\":0,\"content\":\"{\\\"operator\\\":167677,\\\"type\\\":10}\",\"timestamp\":1539314347400,\"secured\":false,\"deleted\":false},{\"messageId\":130,\"type\":\"System\",\"dialogId\":\"C-167677-176215\",\"dialogKeyVer\":0,\"dialogKeyIter\":0,\"iv\":0,\"sender\":0,\"senderDevice\":0,\"content\":\"{\\\"operator\\\":176215,\\\"type\\\":10}\",\"timestamp\":1539324731052,\"secured\":false,\"deleted\":false}],\"relationMessages\":[],\"quoteMessages\":[]}}","cost":4};
var json=JSON.parsse(obj);
alert(json);