var IE = navigator.appName == 'Microsoft Internet Explorer' && navigator.userAgent != 'Opera';
    var SPACER = 'images/spacer.gif';

    if ( IE )
    {
        window.onload = function()
        {
            window.png = new PNGTransparency();
            window.png.create();
        }
    }

    /**
     * Shows the transparency of pngs in internet explorer.
     */
    function PNGTransparency()
    {
        this.create = PNGTransparency_create;
    }

    /**
     * Creates the transparency effect for each image.
     */
    function PNGTransparency_create()
    {
        var i, img, oldsrc;
        var imgs = document.getElementsByTagName( 'IMG' );

        for ( i=0; i < imgs.length; i++ )
        {
            img = imgs[i];

            if ( img.src.indexOf( '.png' ) != -1 )
            {
                oldsrc = img.src;
                img.src = SPACER;
                img.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='" + oldsrc + "', sizingMethod='scale')";
            }
        }
    }