[Octane]

JavaScript (jQuery)

function Panels() {}

Panels.prototype = {
	init: function(select, panels, speed) {
		$.extend(this, {select: $(select), panels: $(panels), speed: speed});
		this.options = this.select.children('option');
		var current = this;
		this.select.change(function() { current.show(); });
		this.panels.hide();
		return this;
	},
	hide: function() {
		this.panels.filter(':visible').slideUp(this.speed);
	},
	show: function() {
		this.hide();
		this.panels.filter(':eq(' + this.options.filter(':selected').val() + ')').slideDown(this.speed);
	}
};

$(function() {
	var myPanels = new Panels().init('#s', '#panels > li', 'slow').show();
});

XHTML:

<form action="">
	<label for="s">Label:
		<select id="s">
			<option value="0" selected="selected">option1</option>
			<option value="1">option2</option>
			<option value="2">option3</option>
		</select>
	</label>
</form>

<ul id="panels">
	<li>panel1</li>
	<li>panel2</li>
	<li>panel3</li>
</ul>

Вот такие вот страсти