在Javascript中运行函数，但最后总是返回“ undefined”

Question

I am quite new to javascript so please excuse if this is a really stupid easy thing to fix and I have missed something minor. My function (below) works as I want it to with the exception that it returns 'undefined' at the end of the log. I have looked through a few other posts that have had their problem rooted in an undefined variable or poor syntax but from what I understood from those that's not my problem (but I'm new so maybe I just didn't understand).

The function should log each value divisible by 4 except values divisible by 100 (with the exception of values divisible by 400, they are still logged).

function Yeah(date){
    var today = new Date().getFullYear();
    if (today % 4 == 0) {
    console.log('This year is a leap year');
}
for(x = today; x > 0; x--){
        if(x % 400 == 0){
        console.log('MEGA leap year' +' '+ x +'!');
    }
    else {
            if (x % 100 == 0) {
                continue;
    }
    else {
                if (x % 4 == 0) {
                    console.log('Leap year' + ' ' + x + '!');
            }
        }
    }
}
}
console.log(Yeah());

Answer 1

Replace console.log(Yeah()); with just Yeah(); . Your function returns undefined since it has no return statements.

You said it works the way you want already, so I assume you don't need it to return anything. In which case you definitely don't need to log its return value.