function colorear(celda)
{
    celda.className='fondocolor';
}
function blanquear(celda)
{
    celda.className='fondoblanco';
}
function ir(celda)
{
    location.href=celda.innerHTML.substring(celda.innerHTML.indexOf("_")+1,celda.innerHTML.indexOf(".gif")) + '.aspx';
}
function sombrear()
{
    altura=screen.height;
    if (altura<=600)
    {
        document.getElementById('imgsombraizq').width='30';
        document.getElementById('imgsombradcha').width='30';
        document.getElementById('celdasombraizq').style.cssText ='background-image:url(images/sombraizq_peq.jpg)';
        document.getElementById('celdasombradcha').style.cssText ='background-image:url(images/sombradcha_peq.jpg)';
    }
}