Так будет понятно?
<!DOCTYPE HTML>
<html>
<body>
<script>
function love(female){
this.name = "Вася";
this.half = female;
this.toString = function(){
alert ( this.name + ' + ' + this.half + " = любовь")
return 'Ok';
}
};
var willfamaly = new love("Лена");
alert(willfamaly);
</script>
</body>
</html>