将javascript Ajax响应与字符串进行比较

我尝试将Ajax调用的结果与字符串进行比较。我的结果是返回正确的结果,但是我不能得到if语句来将它与我的字符串进行比较,有什么想法吗?

      $.ajax({
        type: "POST",
        url: "sessionCheck.php",
        data: {id:mwdata},
        success: function(html) {
            if (html == "open"){
                alert ("yes it's open");   
            }else if(html == "closed"){
                alert ("no it's closed");   
            }  
        }
      });