浏览器和节点之间有什么区别？例如：
节点上的setName.js：
var setName;
setName = function (name) {
return this.name = name;
};
setName("LuLu");
//LuLu
console.log(name);
//undefined
console.log(this.name);
浏览器中的setName.html：
<script>
var setName;
setName = function (name) {
return this.name = name;
};
setName("LuLu");
//LuLu
console.log(name);
//LuLu
console.log(this.name);
</script>
第二个日志不同,为什么？
解决方法
Node是JavaScript引擎,而不是浏览器.您在Node中看到未定义的特定原因,以及浏览器中的Lulu？
Differences in the global namespace：
In browsers,the top-level scope is the global scope. That means that in browsers if you’re in the global scope
var somethingwill define a global variable. In Node this is different. The top-level scope is not the global scope;var somethinginside a Node module will be local to that module.
在浏览器中,这是对窗口对象(浏览器的全局命名空间)的引用,用于所有未附加到对象的函数(例如,不像foo.bar()).在Node中,这不是对全局命名空间的引用.
注：节点解释器中的console.log(this.name)将打印Lulu,而不是未定义.那是因为,仅在REPL中,
> this === global true
进一步阅读@ How To Node: What is “this?”
好的,还有一个编辑按照@Šime Vidas’关于this this的评论提示：
- In the global context (outside of any function),
thisrefers to the global object,whether in strict mode or not.- When the
thiskeyword occurs inside a function,its value depends on 07005.- When a function is called as a method of an object,its
thisis set to the object the method is called on.
更有趣的阅读由one of his blog posts one of his blog posts提供.