$(document).ready(function() {

	var preloadImage = new Array();
	var srcName, state;

	$('.nav_btn').each( function(){
		srcName = $(this).attr('src');
		state = srcName.match(/(.*)_(on|over|off)\.(gif|jpg|jpeg|png)$/i);
		if ( state != null ) {
			switch(state[2]) {
				case 'on':
					//$(this).click($(this).blur());
					break;
				case 'off':
					var i = preloadImage.length;
					preloadImage[i] = new Image();
					preloadImage[i].src = state[1] + "_over." + state[3];

					$(this).mouseover(function(){
						srcName = $(this).attr('src');
						state = srcName.match(/(.*)_(on|over|off)\.(gif|jpg|jpeg|png)$/i);
						$(this).attr('src',state[1] + "_over." + state[3]);
					}).mouseout(function(){
						srcName = $(this).attr('src');
						state = srcName.match(/(.*)_(on|over|off)\.(gif|jpg|jpeg|png)$/i);
						$(this).attr('src',state[1] + "_off." + state[3]);
					});
					break;
			}
		}
	});

});