var l = document.getElementById('inner_left_col').offsetHeight;
var c = document.getElementById('inner_centre_col').offsetHeight;
var r = document.getElementById('inner_right_col').offsetHeight;
var m = r;

if (l > c & l > r)
	{
	m = l;
	}
if (c > l & c > r)
	{
	m = c;
	}
if (r > c & r > l)
	{
	m = r;
	}

document.getElementById('inner_left_col').style.height = m + 'px';
document.getElementById('inner_centre_col').style.height = m + 'px';
document.getElementById('inner_right_col').style.height = m + 'px';