Tell me the difference? Code 1 working 1 time & Code 2 working properly why?

Question

Code 1 -------------------------------

var t = setInterval(move, 500);

var box = document.getElementById("box");

function move() {
var pos = 0;
pos += 1;
box.style.left = pos + "px";
}

Code 2 -------------------------------

var t = setInterval(move, 500);

var box = document.getElementById("box");

var pos = 0;

function move() {
pos += 1;
box.style.left = pos + "px";
}

Code 1 working 1 time & Code 2 working properly why?

Answer 1

oh now I see why ,
"var pos=0" should not be in the move function in code1.everytime move is being called it is returning the value of pos back to 0 therefore the object isnt miving

Answer 2

you should upload the code,not texts of the code