Let it be...
The let statement declares a block scope local variable, optionally initializing it to a value.
What different between var and let ?
It is mathematical statement.Remember in Math class, our teacher always mention let , for example:
The different , notice the code below is using var, once you define same variable in local scope in second time , it will overwrite the variable in global scope,
Using let, help to identify which belong to which.
For details please refer to : let