在ajax-jquery中识别web方法获取的返回值

Question

我写了一个web方法，它有字符串返回value.this返回值获取表单存储过程。但是当条件未被建立时undefined值returned.i写下面的代码但它没有工作

$.ajax(
               { 
type: "POST", 
    url: "WebForm1.aspx/confirm", 
    data: JSON.stringify({ 
    username: username, 
    password: password, email: email,codemeli: codemeli}), 
    contentType: "application/json; charset=utf-8", 
    dataType: "json", 

     async: true, 
     cache: false, 
     success: function (ret) { 

      if (ret != "") { 
      $('#result').text(ret.d + " : " + "it is reserved "+ret.lenght); } 
      else { $('#result').text("the operation is successful"); } 
     }, 
     error: function (x, e) { 
     $('#result').text(x.responseText); 
      } 
      } 
     ); 

Answer 1

ret.lenght应该是ret.d.length在success回调。