Edit in JSFiddle

// 전달받은 매개변수만큼 더해서 반환한다
function sayHi()
{
    var text = "Hello ";
    for (var i in arguments) {
        text += arguments[i] + ' ';
    }
    return text;
}

var text1 = sayHi("JavaScript");
var text2 = sayHi("나에요", 43, '남자');

document.getElementById('demo1').innerText = text1;
document.getElementById('demo2').innerText = text2;

<p id="demo1"></p>

<p id="demo2"></p>