jQuery.fn.autoNumbering = function(options) {
	var defaults = {
		inverted: false,
		delimiter: ". "
	}
 
	var itemsLength = this.length;
	var opts = jQuery.extend(defaults,options);
 
	return this.each(function(index) {
		if(opts.inverted) {
			jQuery(this).prepend(itemsLength+opts.delimiter);
			itemsLength--;
		} else {
			jQuery(this).prepend((index+1)+opts.delimiter);	
		}
	});
};
 
/***TO USE***/
 
$('your element').autoNumbering({inverted:true,delimiter:". "});