JavaScript program to calculate parallelogram circumference

Following program shows you how to calculate parallelogram circumference.
This program gets parallelogram base and side from user and calculates circumference and prints it using following formula
Circumference = 2 X base X side

var parallelogramBase = parseInt(prompt("Please enter base of parallelogram:"));
var parallelogramSide = parseInt(prompt("Please enter side of parallelogram:"));
var circumferenceOfParallelogram = 2 * (parallelogramBase + parallelogramSide);
console.log("Circumference of parallelogram is: " + circumferenceOfParallelogram);

Output:

Please enter base of parallelogram: 
10
Please enter side of parallelogram: 
30
Circumference of parallelogram is: 80.0