Redeclaring a javascript variable

Question

In this tutorial there is written:

If you redeclare a JavaScript variable, it will not lose its value.

Why should I redeclare a variable? Is it

Answer 1

In javascript there is no block scope so it is advisable to redeclare a variable for clarification purposes; this makes for better code.

For example:

for (var x=0; x< 100; x++) { }

alert(x); //In most languages, x would be out of scope here.
          //In javascript, x is still in scope.


//redeclaring a variable helps with clarification: 
var x = "hello";
alert(x);