why is show the string Lilha, George than Lilha angain!!

Hi there,

Let's start with this, from the video:

function greeting() {
  var person = 'Lilah';
  alert(person);
}

var person = 'George';
alert(person);
greeting();

We have two scopes here. One is the global scope, and the other is the scope specific to the greeting() function. At the bottom, we create a variable called "person" that has George stored in it - that one is in the global scope. The "person" variable inside greeting(), set to Lilah, is creating a new variable inside that function's scope, so they are two separate values, and which one you get will depend on where you use "person". If you use that value inside the function, you'll get Lilah, and outside, you'll get George.

This is illustrated by the fact that the alert(person) line under the 'George' person declaration will return George - it is outside the function and in the global scope, where person is set to George. If you call the greeting() function, you'll get Lilah, because the alert(person) for greeting() is inside the function - it will access the "person" variable in the function's scope first, so you get Lilah.

Now, if I read your question correctly, this is the part that was confusing - in the video, he removed the "var" from the line inside the function where he sets person to Lilah, so now the code looks like this:

function greeting() {
  person = 'Lilah'; //right here - no more 'var'
  alert(person);
}

var person = 'George';
alert(person);
greeting();

Something important happens when you remove "var" there - without "var", you are no longer creating a new variable inside the function's scope - you are setting the existing "person" variable in the global scope to Lilah. I'm going to add a line of code at the bottom to illustrate the difference. So, when these four lines run:

var person = 'George';
alert(person);
greeting();
alert(person);

• Line 1 creates a "person" variable, set to "George".
  
• Line 2 does an alert box with "person" in it - George will come up
• Line 3 runs greeting()
• Line 4 does an alert box with "person" in it - Lilah will come up

So, why would Lilah come up on the second alert(person)?

function greeting() {
  person = 'Lilah';    //Line 1
  alert(person);
}

• Line 1: Without a "var" keyword, it will look for an existing "person" variable instead of creating a new one - it finds one, in the global scope. The variable that was set to "George" is now set to "Lilah"

So, when we get to the second alert(person), the variable is now Lilah, because we have run greeting(), which changes that variable's value.

Does that make sense?