/**
 * plugin element operation(visible and hidden)
 * by Daniel Susanto - susantodaniel@gmail.com
 */
jQuery.fn.invisibleEl = function() {
	if(this != null){
		if(this.css('visibility') == 'visible')
			this.css('visibility', 'hidden');
	}
}

jQuery.fn.visibleEl = function() {
	if(this != null){
		if(this.css('visibility') == 'hidden')
			this.css('visibility', 'visible');
	}
}