[Riim]

Примерно так (псевдокод):

var MyClass = function(elem) {
	this.elem = $(elem);
	var self = this;
	Event.add(this.elem, 'mouseover', function() {self.mouseover()});
	Event.add(this.elem, 'mouseout', function() {self.mouseout()});
};

MyClass.prototype.mouseover = function() {
	this.elem.innerHTML = 'over';
};

MyClass.prototype.mouseout = function() {
	this.elem.innerHTML = 'out';
};

$.ready(function() {
	new MyClass('div1');
});