Codice PHP:
function tableruler()
{
    if (
document.getElementById && document.createTextNode)
    {
    var 
tables=document.getElementsByTagName('table');
    for (var 
i=0;i<tables.length;i++)
    {
        if(
tables[i].className=='ruler')
        {
            var 
trs=tables[i].getElementsByTagName('tr');
            for(var 
j=0;j<trs.length;j++)
            {
                if(
trs[j].parentNode.nodeName=='TBODY')
                {
                    
trs[j].onmouseover=function(){this.className='ruled';return false}
                    
trs[j].onmouseout=function(){this.className='';return false}
                    
trs[j].onclick=function()
                        {
                        var 
messaggio "celle trovate nella riga... ";

                        var 
tdsthis.getElementsByTagName('td');
                        
messaggio += "\n num.tag ="+tds.length+"\n";

                        for(var 
y=0;y<tds.length;y++) 
                            {
                            var 
valcell=tds[y].firstChild
                            for (var 
prop in valcell)
                                {
                                if (
prop == "nodeValue") {
                                    
messaggio+="\n num.cella: "+y;
                                    
messaggio += "\n >>> proprietà."+prop+" = "+valcell[prop];
                                    }
                                }

                            
messaggio+="\n ----------------------------------";
                            }
                        
window.alert(messaggio);
                        
location.href=destinazione;
                        return 
false;
                        }
                        
                }
            }
        }
    }
    }

Ho risolto in questo modo...
Funziona con IE 6.0 e FireFox 2.0

Grazie a tutti per la collaborazione.