/********************************
*   (C) 2009 - Thiago Barbedo   *
*   - tbarbedo@gmail.com        *
*********************************/
window.onscroll = function()
{
    if( window.XMLHttpRequest ) {
        if (document.documentElement.scrollTop > 279 || self.pageYOffset > 279) {
            $('#menu_fixed').css('position','fixed');
            $('#menu_fixed').css('top','0');
            	
        } else if (document.documentElement.scrollTop < 279 || self.pageYOffset < 279) {
            $('#menu_fixed').css('position','absolute');
            $('#menu_fixed').css('top','279px');
        }
    }
}