How to add two strings as if they were numbers? [duplicate]

Answer 1

I would recommend to use the unary plus operator, to force an eventual string to be treated as number, inside parenthesis to make the code more readable like the following:

(+varname)

So, in your case it's:

var num1 = '20',
    num2 = '30.5';

var sum = (+num1) + (+num2);

// Just to test it
console.log( sum ); // 50.5