HTML hidden td takes white space in IE6

I am developing one JavaScript script the will hide and show the td on the my button click.

When I am trying to hide the td than IE6 hide the td and put the some spaces there but however my code is working on the all the latest morder browser even the latest IE.

My code:

data = getElementsByClassName("data", "td", myElement);
for (i = 0; i < data.length; i++) {
    td = data[i];                        
    tr = td.parentNode;
    for (j = 0; j < tr.childNodes.length; j++) {        
        tr.childNodes[j].style.display = "none";
    }
}

Here I wrote my own getElementsByClassName method becusae the IE6 does not support it and I want the IE6 support. above code works find in all other browsers except the IE6 browser.

In IE6 my table look like this:

And in other browsers

Thanks for the help.