function insert_bb(aTag, eTag, formName, inputName)
{
	var input = document.forms[formName].elements[formName+'_'+inputName];
	input.focus();

	if (typeof document.selection != "undefined") {
		/* für Internet Explorer */
		var range = document.selection.createRange();
		var insText = range.text;
		range.text = aTag + insText + eTag;
		range = document.selection.createRange();

		if (insText.length == 0)
			range.move('character', -eTag.length);
		else
			range.moveStart('character', aTag.length + insText.length + eTag.length);

		range.select();
	} else if (typeof input.selectionStart != "undefined") {
		/* für neuere auf Gecko basierende Browser */
		var start = input.selectionStart;
		var end = input.selectionEnd;
		var insText = input.value.substring(start, end);
		input.value = input.value.substr(0, start) + aTag + insText + eTag + input.value.substr(end);
		var pos;

		if (insText.length == 0)
			pos = start + aTag.length;
		else
			pos = start + aTag.length + insText.length + eTag.length;

		input.selectionStart = pos;
		input.selectionEnd = pos;
	} else {
		/* für die übrigen Browser */
		var pos;
		var re = new RegExp('^[0-9]{0,3}$');

		while (!re.test(pos))
			pos = prompt("Einfügen an Position (0.." + input.value.length + "):", "0");
		if (pos > input.value.length)
			pos = input.value.length;

		var insText = prompt("Bitte geben Sie den zu formatierenden Text ein:");
		input.value = input.value.substr(0, pos) + aTag + insText + eTag + input.value.substr(pos);
	}
}