alert("Hello World");

var WORLD = "World";
function hello(who) {
    alert("Hello " + who);
};
hello(WORLD);

<button onclick="hello(WORLD)">Say Hello</button>

<button id="hello">Say Hello</button>

var button = document.all.hello;
button.onclick = function() {
    hello(WORLD);
};

var button = document.getElementById("hello");
button.addEventListener("click", function(event) {
    hello(WORLD);
}, false);

var Hello = new Binding({
    greet: function(who) {
        alert("Hello " + who);
    },
    
    onclick: function() {
        this.greet(Hello.WORLD)
    }
}, {
    WORLD: "World"
});
document.bind("#hello", Hello);