We can do both sdies (Scripting and Designing)
we have 2 types of variables SET and LET
Using SET you are adding string value to a variable
returns variable value is= '4+5'
using LET you are adding an expression result to a variable
returns variable value is= 9
Hope you understand..................
Yes and in front end you can assign the value to variable by the help of the input box.
Let xVar = 0;
In front end by input box enter any value by using this variable.
Or you can check Henric Explanation
Check this for better understanding.