/**
 * define spacer image used by alphapng functions
 */
var spacerImage = 'images/common/spacer.gif';

/**
 * fix alpha png backgrounds on a page (turn on transparency for IE)
 * @param string support html tag (i.e. "DIV")
 */
function _fixAlphaPngBackground(htmltag)
{
    var src     = '';
    var ua      = '';
    var rpng    = new RegExp('url\\(([a-zA-Z0-9_/:-]+\.png)\\)');
    var rmsie   = new RegExp('msie');
    var rmac    = new RegExp('mac');

    if (document.all)
    {
        var l = document.getElementsByTagName(htmltag).length;
        for (var i = 0; i < l; i++)
        {
            src = document.getElementsByTagName(htmltag)[i].style.backgroundImage;
            ua  = navigator.userAgent.toLowerCase();

            if (src.match(rpng) && ua.match(rmsie) && !ua.match(rmac))
            {
            	src = src.replace(rpng, '$1');
                document.getElementsByTagName(htmltag)[i].style.backgroundImage = 'none';
                document.getElementsByTagName(htmltag)[i].style.filter = 'progid:DXImageTransform.Microsoft.AlphaImageLoader(enabled=\'true\', sizingMethod=\'scale\', src=\'' + src + '\')';
            }
        }
    }
}

/**
 * fix alpha pngs on a page (turn on transparency for IE)
 */
function fixAlphaPng()
{
    var src     = '';
    var ua      = '';
    var width   = '';
    var height  = '';
    var rpng    = new RegExp('\.png$');
    var rmsie   = new RegExp('msie');
    var rmac    = new RegExp('mac');

    if (document.all)
    {
        for (var i = 0; i < document.getElementsByTagName('IMG').length; i++)
        {
            src     = document.getElementsByTagName('IMG')[i].getAttribute('src').toLowerCase();
            ua      = navigator.userAgent.toLowerCase();
            width   = document.getElementsByTagName('IMG')[i].getAttribute('width');
            height  = document.getElementsByTagName('IMG')[i].getAttribute('height');

            if (src.match(rpng) && ua.match(rmsie) && !ua.match(rmac))
            {
            	document.getElementsByTagName('IMG')[i].setAttribute('src', spacerImage);
                document.getElementsByTagName('IMG')[i].style.filter = 'progid:DXImageTransform.Microsoft.AlphaImageLoader(enabled=\'true\', src=\'' + src + '\', sizingMethod=\'scale\')';
                document.getElementsByTagName('IMG')[i].style.width = width + 'px';
                document.getElementsByTagName('IMG')[i].style.height = height + 'px';
            }
        }

        _fixAlphaPngBackground('DIV');
        _fixAlphaPngBackground('TABLE');
        _fixAlphaPngBackground('TD');
    }
}

addEvent(window, 'load', fixAlphaPng);