/***
@title:
Center

@version:
2.0

@author:
Andreas Lagerkvist

@date:
2008-09-17

@url:
http://andreaslagerkvist.com/jquery/center/

@license:
http://creativecommons.org/licenses/by/3.0/

@copyright:
2008 Andreas Lagerkvist (andreaslagerkvist.com)

@requires:
jquery

@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) {
    return this.each(function () {
        var t = jQuery(this);

        t.css({
            position: absolute ? 'absolute' : 'fixed',
            left: '50%',
            top: '50%'
            /* ,zIndex: '99' */
        }).css({
            marginLeft: '-' + (t.outerWidth() / 2) + 'px',
            marginTop: '-' + (t.outerHeight() / 2) + 'px'
        });

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