Design Issue In Fire Fox (td compressed)

when we show hide some table <td> with javascript then the data of  both tds got stretched the code is:
if(CheckBox1.checked)
        {        
            objTable.style.display = "block";
            trMoreListing.style.display = "block"; 
        }
        else
        {
             objTable.style.display = "none";
             trMoreListing.style.display = "none";            
        }

Solution:
Instead of this
trMoreListing.style.display = "block";
use
trMoreListing.style.display = "";