$(document).ready(function(){
	/* this code is executed after the dom has been completely loaded */
	
	var totwidth=0;
	var positions = new array();
	
	$('#slides .slide').each(function(i){
		
		/* traverse through all the slides and store their accumulative widths in totwidth */
		
		positions[i]= totwidth;
		totwidth += $(this).width();
		
		/* the positions array contains each slide's commulutative offset from the left part of the container */
		
		if(!$(this).width())
		{
			alert("please, fill in width & height for all your images!");
			return false;
		}
		
	});
	
	$('#slides').width(totwidth);

	/* change the cotnainer div's width to the exact width of all the slides combined */

	$('#menu ul li a').click(function(e,keepscroll){

			/* on a thumbnail click */

			$('li.menuitem').removeclass('act').addclass('inact');
			$(this).parent().addclass('act');
			
			var pos = $(this).parent().prevall('.menuitem').length;
			
			$('#slides').stop().animate({marginleft:-positions[pos]+'px'},450);
			/* start the sliding animation */
			
			e.preventdefault();
			/* prevent the default action of the link */
			
			
			// stopping the auto-advance if an icon has been clicked:
			if(!keepscroll) clearinterval(itvl);
	});
	
	$('#menu ul li.menuitem:first').addclass('act').siblings().addclass('inact');
	/* on page load, mark the first thumbnail as active */
	
	
	
	/*****
	 *
	 *	enabling auto-advance.
	 *
	 ****/
	 
	var current=1;
	function autoadvance()
	{
		if(current==-1) return false;
		
		$('#menu ul li a').eq(current%$('#menu ul li a').length).trigger('click',[true]);	// [true] will be passed as the keepscroll parameter of the click function on line 28
		current++;
	}

	// the number of seconds that the slider will auto-advance in:
	
	var changeevery = 4;

	var itvl = setinterval(function(){autoadvance()},changeevery*1000);

	/* end of customizations */
});