Sum numbers from the visitor

We want to make this open-source project available for people all around the world.

Help to translate the content of this tutorial to your language!

Create a script that prompts the visitor to enter two numbers and then shows their sum.

P.S. There is a gotcha with types.

solution

let a = +prompt("The first number?", "");
let b = +prompt("The second number?", "");

alert( a + b );

Note the unary plus + before prompt. It immediately converts the value to a number.

Otherwise, a and b would be string their sum would be their concatenation, that is: "1" + "2" = "12".