声明变量不带var，JS会在全局对象中创建一个同名属性，坑爹 JS在函数作用域上倒是和Python有些相似，不过Python是直接抛出错误，而JS是打印出undefined. .. code:: python >>> def foo(): ... print(a) ... a = 1 ... >>> foo() Traceback (most recent call last): ...
声明变量不带var，JS会在全局对象中创建一个同名属性，坑爹 JS在函数作用域上倒是和Python有些相似，不过Python是直接抛出错误，而JS是打印出undefined. .. code:: python >>> def foo(): ... print(a) ... a = 1 ... >>> foo() Traceback (most recent call last): ...
