How is the memory allocation done for variables in scripting languages?

Question

For example, in javascript

I can say

var x = 5;

Later I can do

x = \'a\';

and then

Answer 1

Python uses a technique called reference counting, which basically puts a counter in the value. Each time a reference to a value is created, the counter is incremented. When a reference to the value is lost (for instance when you assign a new value to 'x'), the value is decremented. When the counter reaches zero, that means that no reference to the value exists, and it can be deallocated. This is a simplified explanation, but that's at least the basics.