function $(id) {
	var el = arguments.callee[id];
	if(typeof el == 'undefined') el = arguments.callee[id] = document.getElementById(id);
	return el;
}

function styleColumn(table,n,style) {
	var i,trs,tds,k;
	trs = table.getElementsByTagName("TR");
	for(i=0;i<trs.length;i++) {
		tds = trs[i].getElementsByTagName("TD");
		for(k in style) tds[n].style[k] = style[k];
	}
}

function getColumns(table,f) {
	var i,tr,tds,ret;
	ret = [];
	tr = table.getElementsByTagName("TR")[0];
	tds = tr.getElementsByTagName("TD");
	for(i=0;i<tds.length;i++) if(f(tds[i])) ret.push(i);
	return ret;
}

function select(table,n) {
	var i,visible;
	visible = getColumns(table,function(el){return el.display != 'none';});
	for(i=0;i<visible.length;i++)
		if(visible[i] != 0)
			styleColumn(table,visible[i],{display: 'none'})
	if(n >= 0) styleColumn(table,n,{display: ''});
}