JavaScript quiz. What will be printed to the console as a result? <

What will be printed to the console as a result?

 var a;
switch(a)
{
    case 0: 
        alert('0'); 
        break;
    case null: 
        alert('null'); 
        break;
    case undefined: 
        alert('undefined'); 
        break;
    default:
        alert('something else');
}

Explanation

Switch acts like a big if / else if / else chain. Checks a value against a list of cases, and executes the first case that is true. Example:


    function printValue(value){
        switch (value) {
            case 1:
                console.log('number one');
                break;
            case 2:
                console.log('second one');
                break;
            default :
                console.log('third one');
        }
    }
    printValue(1); // will print 'number one'
    printValue(2); // will print 'second one'
    printValue(3); // will print default value
//The default keyword specifies the code to run if there is no case match