var pl_display_c = new Array();

function pl_display(id){
	if (!pl_display_c[id] || pl_display_c[id] == "none"){
		document.getElementById("pl_display_c" + id).style.display = 'block';
		pl_display_c[id] = 'block';
	} else {
		document.getElementById("pl_display_c" + id).style.display = 'none';
		pl_display_c[id] = 'none';
	}
}