javascript 内部函数无法访问外部函数变量
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Inner function cannot access outer functions variable
提问by Decrypter
I have created the following jsfiddle which highlights my problem. http://jsfiddle.net/UTG7U/
我创建了以下 jsfiddle，它突出了我的问题。 http://jsfiddle.net/UTG7U/
var ExampleObject = function() {
var myArray = new Array();
this.example = function() {
alert(this.myArray);
};
}
var exampleObj = new ExampleObject();
exampleObj.example();?
I am new to JavaScript and trying to create an object, field and a method. I can't get my method to access my field variable.
我是 JavaScript 新手，正在尝试创建对象、字段和方法。我无法使用我的方法来访问我的字段变量。
回答by Saket Patel
you were trying to access a local variable using this operator which is wrong, so here is the working example
您试图使用此运算符访问局部变量，这是错误的，所以这是工作示例
var ExampleObject = function() {
var myArray = new Array(1,2,3);
this.example = function() {
alert(myArray);
};
}
var exampleObj = new ExampleObject();
exampleObj.example();?
回答by Raymond Chen
You have confused two types of variables: Local variables and member variables. var myArrayis a local variable. this.myArrayis a member variable.
你混淆了两种类型的变量：局部变量和成员变量。var myArray是局部变量。this.myArray是成员变量。
Solution using only local variables:
仅使用局部变量的解决方案：
var ExampleObject = function() {
var myArray = new Array(); // create a local variable
this.example = function() {
alert(myArray); // access it as a local variable
};
}
var exampleObj = new ExampleObject();
exampleObj.example();?
Solution using only member variables:
仅使用成员变量的解决方案：
var ExampleObject = function() {
this.myArray = new Array(); // create a member variable
this.example = function() {
alert(this.myArray); // access it as a member variable
};
}
var exampleObj = new ExampleObject();
exampleObj.example();?
回答by Rhyono
You don't need the this.myArray. Using myArrayalone will suffice (and work).
你不需要this.myArray. myArray单独使用就足够了（并且有效）。
回答by SNAG
alert(myArray);should work fine I think
alert(myArray);我认为应该可以正常工作
回答by Oliver Moran
What thisis changes with the scope of each function. However, myArraywill be visible to inner function. Example:
this每个功能的范围会发生什么变化。但是，myArray对内部函数是可见的。例子：
var ExampleObject = function() {
var myArray = new Array();
this.example = function() {
alert(myArray);
};
}
var exampleObj = new ExampleObject();
exampleObj.example();?
