Question

Possible Duplicate:
JavaScript Variable Scope

var flag = false;
if(flag === true)
{
     var you = "great";
}

Variable “you” is initialized with undefined, it shows undefined instead of showing reference error when printed. why?

Answer 1

In Javascript, all variables are “hoisted” to the top of the function/scope they’re declared in. That is, your code REALLY looks like this to the compiler:

var flag = false;
var you;
if (flag === true)
{
    you = "great"
}