[JavaScript] NS_ERROR_XPC_NOT_ENOUGH_ARGS

function add(cod) {
var bal = document.getElementById(cod).value;
var v2 = '</'+cod+'>';
if (cod == "code") { var val = '<code language="'+bal+'" title="">'; }
else if (cod == "colo") { var val = '<color="'+bal+'">'; }
var text = document.getElementById("textarea");
		if (text.curseur) {
		text.curseur.text = val + text.curseur.text + v2;
		}
		else if (text.selectionStart >= 0 && text.selectionEnd >= 0) {
		var debu = text.value.substring(0, text.selectionStart);
		var enter = text.value.substring(text.selectionStart, text.selectionEnd);
		var fin = text.value.substring(text.selectionEnd);
		text.value = debu + val + enter + v2 + fin;
		text.focus();
		text.setSelectionRange(debu.length + val.length, text.value.length - fin.length - v2.length);
		}
		else {
		text.value += val + v2;
		text.focus();
		}
document.getElementById(cod).options[0].selected = true;
}

<select class="kit" style="width: 120px;" id="code" onchange="add('code');">