javascript - javascript 中缺少值(未定义)

Question

我有带有键值对的对象列表。当我将它们分开以在特定字段上显示每个信息时。我收到类型错误 data.validation[i].user is undefined但是我检查过变量已经赋值。

var data = {validation:[
{"user":"user may not be empty"},
{"date":"Date may not be null"},
{"mobile":"passengerMobile may not be empty"},
{"mobileSize":"passengerMobile size must be greater than 11"},
{"name":"passengerName may not be empty"},
{"nameSize":"passengerName size must be between 2 and 30"},
 ]};

var size = data.validation.length;

for(var i =0;i<=size;i++){
if(data.validation[i].user){
 $("#username").html("<p>"+data.validation[i].user+"</p>");
  }
  if($("#mobile").val().length == 0){
    $("#mobilesize").html("<p>"+data.validation[i].mobile+"</p>");
    }
    else if($("#mobile").val().length >= 1){
    $("#mobilesize").html("<p>"+data.validation[i].mobilesize+"</p>");
    }
  }

$("#mobile") 表示输入字段Id

热烈欢迎任何想法

Answer 1

仅使用少于此处的旅游条件。因为它从 0,1,2,.... 开始

for(var i =0;i<size;i++)

你的长度是 6，但最后一次获取时应该是

data.validation[5].user

你正确的代码应该是:

  var size = data.validation.length;

    for(var i =0;i<size;i++){
    if(data.validation[i].user){
     $("#username").html("<p>"+data.validation[i].user+"</p>");
      }
      if($("#mobile").val().length == 0){
        $("#mobilesize").html("<p>"+data.validation[i].mobile+"</p>");
        }
        else if($("#mobile").val().length >= 1){
        $("#mobilesize").html("<p>"+data.validation[i].mobilesize+"</p>");
        }
      }