Setting Style Display property

click on the table headers..

TH: click to toggle('row1d')
some table data
TH: click to toggle('row2d')
some table data
TH: click to toggle('row3d')
some table data
TH: click to toggle('row4d')
some table data
TH: click to toggle('row5d')
some table data

some more stuff below the table...

my code: 
function toggle(id)
{
	el = document.getElementById(id);
	var display = el.style.display ? '' : 'none';
	el.style.display = display;
}

I'm getting funky results in NN6 (v6.1)
setting display to block or inline doesn't work either....