salve a tutti.

Sto avendo problemi nell'inserimento di bbcode in una textarea.

JAVASCRIPT
codice:
function ddcode(code){
	
	if (isMozilla) 
	{
	// Si on est sur Mozilla

		oField = document.forms['newevent'].elements['txtevent'];

		objectValue = oField.value;

		deb = oField.selectionStart;
		fin = oField.selectionEnd;

		objectValueDeb = objectValue.substring( 0 , oField.selectionStart );
		objectValueFin = objectValue.substring( oField.selectionEnd , oField.textLength );
		objectSelected = objectValue.substring( oField.selectionStart ,oField.selectionEnd );

	//	alert("Debut:'"+objectValueDeb+"' ("+deb+")\nFin:'"+objectValueFin+"' ("+fin+")\n\nSelectionné:'"+objectSelected+"'("+(fin-deb)+")");
			
		oField.value = objectValueDeb + "[" + code + "]" + objectSelected + "[/" + code + "]" + objectValueFin;
		oField.selectionStart = strlen(objectValueDeb);
		oField.selectionEnd = strlen(objectValueDeb + "[" + code + "]" + objectSelected + "[/" + code + "]");
		oField.focus();
		oField.setSelectionRange(
			objectValueDeb.length + selec.length + 2,
			objectValueDeb.length + selec.length + 2);
	}
	else
	{
	// Si on est sur IE
		
		oField = document.forms['newevent'].elements['txtevent'];
		var str = document.selection.createRange().text;

		if (str.length>0)
		{
		// Si on a selectionné du texte
			var sel = document.selection.createRange();
			sel.text = "[" + code + "]" + str + "[/" + code + "]";
			sel.collapse();
			sel.select();
		}
		else
		{
			oField.focus(oField.caretPos);
		//	alert(oField.caretPos+"\n"+oField.value.length+"\n")
			oField.focus(oField.value.length);
			oField.caretPos = document.selection.createRange().duplicate();
			
			var bidon = "%~%";
			var orig = oField.value;
			oField.caretPos.text = bidon;
			var i = oField.value.search(bidon);
			oField.value = orig.substr(0,i) + "[" + code + "][/" + code + "]" + orig.substr(i, oField.value.length);
			var r = 0;
			for(n = 0; n < i; n++)
			{if(regexp.test(oField.value.substr(n,2)) == true){r++;}};
			pos = i + 2 + code.length - r;
			//placer(document.forms['news'].elements['newst'], pos);
			var r = oField.createTextRange();
			r.moveStart('character', pos);
			r.collapse();
			r.select();

		}
	}
	
}
HTML
codice:
<form name="newevent" method="post" action="sendnewevent.php" onsubmit="return ctrlnewevent(this)">
<input type="button" name="btStrong" id="btStrong" value="B" onclick="ddcode('B')">
<input type="button" name="btEm" id="btEm" value="I" onclick="ddcode('I')">
<input type="button" name="btU" id="btU" value="U" onclick="ddcode('U')">
non inserisce nulla nella textarea