How to associate functions with objects using JavaScript?

Let's now create a custom "toString()" method for our movie object. We can embed the function directly in the object like this.

<script type="text/javascript">

function movie(title, director) {

this.title = title;

this.director = director;

this.toString = function movieToString() {

return("title: "+this.title+" director: "+this.director);

}

}

var narnia = new movie("Narni","Andrew Adamson");

document.write(narnia.toString());

</script>

This produces

title: Narni director: Andrew Adamson

Or we can use a previously defined function and assign it to a variable. Note that the name of the function is not followed by parenthesis, otherwise it would just execute the function and stuff the returned value into the variable.

<script type="text/javascript">

function movieToString() {

return("title: "+this.title+" director: "+this.director);

}

function movie(title, director) {

this.title = title;

this.director = director;

this.toString = movieToString; //assign function to this method pointer

}

var aliens = new movie("Aliens","Cameron");

document.write(aliens.toString());

</script>

This produces

title: Aliens director: Cameron