/***
@does:
This little pluggy centers an element on the screen using either fixed or absolute positioning. Can be used to display messages, pop up images etc.

@howto:
jQuery('#my-element').center(true); would center the element with ID 'my-element' using absolute position (leave empty for fixed).

@exampleHTML:
<p>I should be fixed centered</p>

<p>The paragraph above and the paragraph beneath this one are centered. They should be in the middle of the viewport.</p>

<p>I should be absolutely centered</p>

@exampleJS:
jQuery('#jquery-center-example p:first-child').center();
jQuery('#jquery-center-example p:last-child').center(true);
***/
jQuery.fn.center = function (absolute,custom) {
	return this.each(function () {
		var t = jQuery(this);

		t.css({
			position:	absolute ? 'absolute' : 'fixed', 
			left:		'50%', 
			top:		'50%'
			//commento z-index al momento non mi serve
			, 
			zIndex:		'1'
		}).css({
			marginLeft:	'-' + (t.outerWidth() / 2) + 'px', 
			marginTop:	'-' + ((t.outerHeight()+(custom==null?140:custom)) / 2) + 'px'
		});

		if (absolute) {
			t.css({
				marginTop:	parseInt(t.css('marginTop'), 10) + jQuery(window).scrollTop(), 
				marginLeft:	parseInt(t.css('marginLeft'), 10) + jQuery(window).scrollLeft()
			});
		}
	});
};