javascript: Why does this code result in an error.?

Question

I'm not trying to fix it. I just want to know why it results in the error:

ReferenceError: prisoner_2 is not defined

The code:

function prison(){
	prisoner_1='I have escaped';
	var prisoner_2='I am locked in';
};

prison();
console.log(prisoner_1);
console.log(prisoner_2);

Anonym · Accepted Answer

Because it is declared within the function with a VAR which means it is only seen within the function - it is locked in.

Compare with...

function prison(){ 
prisoner_1='I have escaped'; 
var prisoner_2='I am locked in';

alert(prisoner_2)

};

prison();

prisoner_2 = "I escaped too!"

console.log(prisoner_1); 
console.log(prisoner_2);

Sadsongs · Answer

Because prisoner_2 is declared in function prison() and so is only in scope for that function.

You could make it global or, better, declare it in the main body and pass it to the function as argument.