function applyZebra() { 
    var tables = document.getElementsByTagName("table"); 
    for(var i=0, length=tables.length; i<length; i++) { 
        if (tables[i].className.indexOf("zebra")>=0) { 
            var tbody = tables[i].getElementsByTagName("tbody"); 
            var table = (tbody[0]?tbody[0]:tables[i]); 
            var trs = table.getElementsByTagName("tr"); 
            for(var j=0, lengthj=trs.length; j<lengthj; j++) { 
                if (j%2==0) trs[j].className='even';else trs[j].className='odd'; 
            } 
        } 
    } 
}