“这个”是什么意思？指的是使用它的函数被称为“new myFunction(“Hello”)`
function myFunction(message)
{
this.message = message;
return this.message;
}
document.body.innerHTML = new myFunction("Hello");
我了解到“在 JavaScript 中 this 始终指的是我们正在执行的函数的‘所有者’，或者更确切地说，指的是函数所属的对象。” reference
在此示例中，myFunction 中的 this 似乎应该引用myFunction 然后是窗口。不过，它似乎指的是 myFunction 。这是为什么呢？
function myFunction(message)
{
this.message = message;
return this.message;
}
document.body.innerHTML = new myFunction("Hello");
I learnt that "in JavaScript this always refers to the 'owner' of the function we're executing, or rather, to the object that a function is a method of." reference
In this example it would seem that the this in myFunction should refer to the owner of the myFunction then, the window. It seems like it's referring to the myFunction though. Why is this?
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当您使用
new运算符时，您会创建 构造函数和this引用新对象。通过添加 new 关键字完全改变了问题之前的旧答案：
因为myFunction未使用new关键字调用，或者在显式上下文中调用另一个对象，它实际上是：document.body.innerHTML = window.myFunction("Hello");所以this是window对象。您可以通过将函数编辑到console.log来确认这一点，无论this是什么，然后在 Firebug 中查找。< /删除>When you use the
newoperator, you create a new instance of an object defined in the constructor function andthisrefers to the new object.Old answer before the question was completely changed by the addition of the new keyword:
SincemyFunctionis not being called with thenewkeyword, or in the explicit context of another object, it is effectively:document.body.innerHTML = window.myFunction("Hello");Sothisis thewindowobject.You can confirm this by editing the function toconsole.logwhateverthisis and then looking in Firebug.如果您调用
new myFunction("hello")，则this引用一个继承自函数的新“空”对象（它不引用该函数！）原型属性（myFunction.prototype）。这样的函数也称为构造函数，并且习惯上名称以大写字母开头。
If you call
new myFunction("hello"), thenthisrefers to a new "empty" object (it does not refer to the function!) that inherits from the functions prototype property (myFunction.prototype).Such a function is also called constructor function and it is convention to start the name with a capital letter.