How would one access javascript function's return value outside of the function? For example could you tell a function to return something somewhere else in the code? Theoretical example:

milkmachine = function(argument){
    var r;
    var k;
    //do something with arguments and variables
    return r;
}
var rainbow = milkmachine(); //rainbow == r
milkmachine.return(k);
var spectrum = milkmachine(); //spectrum == k