What does javascript function return in the absence of a return statement?

前端未结

关注

 3  1689

I was just wondering, does a function without a return statement (or without hitting any return statements) return a value that is completely equivalent to false?

相关标签:

3条回答

傲寒

2020-11-27 05:51
to find out, try this in firebug console:
```
alert((function(){})());
```
0 讨论(0)
发布评论:

提交评论
- 加载中...

清歌不尽

2020-11-27 06:12

<html>
<body>
<script>
function a() {}
alert(a());
</script>
</body>
</html>

0 讨论(0)

猫巷女王i

2020-11-27 06:18
A function without a return statement (or one that ends its execution without hitting one) will return undefined.

And if you use the unary negation operator twice on an undefined value, you will get false.

You are not seeing anything on the console because Firebug doesn't prints the result of an expression when it's undefined (just try typing undefined; at the console, and you will see nothing).

However if you call the console.log function directly, and you will be able to see it:
```
function foo(){}

console.log(foo()); // will show 'undefined'
```
0 讨论(0)
发布评论:

提交评论
- 加载中...