我仍然是JavaScript的初学者，但我写了一个小函数来递归地打印对象及其子对象的所有属性:

getDescription(object, tabs) {
  var str = "{\n";
  for (var x in object) {
      str += Array(tabs + 2).join("\t") + x + ": ";
      if (typeof object[x] === 'object' && object[x]) {
        str += this.getDescription(object[x], tabs + 1);
      } else {
        str += object[x];
      }
      str += "\n";
  }
  str += Array(tabs + 1).join("\t") + "}";
  return str;
}

简单JavaScript代码:

for(var propertyName in myObject) {
   // propertyName is what you want.
   // You can get the value like this: myObject[propertyName]
}

jQuery:

jQuery.each(obj, function(key, value) {
   // key is what you want.
   // The value is in: value
});

for (prop in obj) {
    alert(prop + ' = ' + obj[prop]);
}

下面是如何枚举一个对象的属性:

var params = { name: 'myname', age: 'myage' }

for (var key in params) {
  alert(key + "=" + params[key]);
}

简单:

for(var propertyName in myObject) {
   // propertyName is what you want
   // you can get the value like this: myObject[propertyName]
}

现在，您不会以这种方式获得私有变量，因为它们不可用。

编辑:@bitwiseplatypus是正确的，除非你使用hasOwnProperty()方法，否则你将获得继承的属性-然而，我不知道为什么任何熟悉面向对象编程的人会期望更少!一般来说，提出这个问题的人都听过道格拉斯·克罗克福德的警告，这让我有点困惑。同样，继承是OO语言的一个正常部分，因此也是JavaScript的一部分，尽管它是原型。

现在，也就是说，hasOwnProperty()对于过滤是有用的，但我们不需要发出警告，就好像获取继承属性是危险的一样。

EDIT 2: @bitwiseplatypus brings up the situation that would occur should someone add properties/methods to your objects at a point in time later than when you originally wrote your objects (via its prototype) - while it is true that this might cause unexpected behavior, I personally don't see that as my problem entirely. Just a matter of opinion. Besides, what if I design things in such a way that I use prototypes during the construction of my objects and yet have code that iterates over the properties of the object and I want all inherited properties? I wouldn't use hasOwnProperty(). Then, let's say, someone adds new properties later. Is that my fault if things behave badly at that point? I don't think so. I think this is why jQuery, as an example, has specified ways of extending how it works (via jQuery.extend and jQuery.fn.extend).

我找到了……For (property in object) {// do stuff}将列出所有属性，因此所有全局声明的变量在窗口对象上。