window.variableName

Question

I am going through some code and at the beginning of the script we have var emailID = email. Later on, the code refers to emailID by going window.emailID<

Answer 1

Global Variables in JavaScript

var no =10;
function getNo()
   alert(no); // 10
}
getNo();

When a global variable is set, it's added to the window object!

var no =10;
function getNo()
   alert(window.no); // 10
}
getNo();

We can direct set window variable.

function setNo(){
  window.no=100;
}
function getNo()
   alert(window.no); // 100
}
setNo();
getNo();