Why this kind of function invocation is wrong in JavaScript?
function, invocation, javascript
Solution
The ECMAScript Language Specification, section 12.4, says:
An ExpressionStatement cannot start with the `function` keyword because that might make it ambiguous with a FunctionDeclaration.
So your case 1 is not allowed, because it might lead to ambiguities in the language. The other cases are different kinds of statements (not ExpressionStatements) in which this is not a problem, so the construct is allowed there.
Problem
I'd like to create an anonymous function and then invoke it immediately. 1) This will bring a syntax error. Why? ``` function () { alert("hello"); }(); ``` 2) wrap the function definition with () and it works. ``` (function () { alert("hello"); })(); ``` 3) or, assign the anonymous function to a variable. It works. ``` var dummy = function() { alert("hello"); }(); ``` Why the first way doesn't work?