javascript bb code bar met greasemonkey

function addText(id, wrap1, wrap2) {
	if (document.selection) { // for IE 
		var str = document.selection.createRange().text;
		document.getElementById(id).focus();
		var sel = document.selection.createRange();
		sel.text = wrap1 + str + wrap2;
		return;
	} else if ((typeof document.getElementById(id).selectionStart) != 'undefined') { // for Mozilla
		var txtarea = document.getElementById(id);
		var selLength = txtarea.textLength;
		var selStart = txtarea.selectionStart;
		var selEnd = txtarea.selectionEnd;
		var oldScrollTop = txtarea.scrollTop;
		//if (selEnd == 1 || selEnd == 2)
		//selEnd = selLength;
		var s1 = (txtarea.value).substring(0,selStart);
		var s2 = (txtarea.value).substring(selStart, selEnd)
		var s3 = (txtarea.value).substring(selEnd, selLength);
		txtarea.value = s1 + wrap1 + s2 + wrap2 + s3;
		txtarea.selectionStart = s1.length;
		txtarea.selectionEnd = s1.length + s2.length + wrap1.length + wrap2.length;
		txtarea.scrollTop = oldScrollTop;
		txtarea.focus();
		return;
	} else {
		insertText(foname, elname, wrap1 + wrap2);
	}
}


function insertText(id, what) {
	if (document.getElementById(id).createTextRange) {
		document.getElementById(id).focus();
		document.selection.createRange().duplicate().text = what;
	} else if ((typeof document.getElementById(id).selectionStart) != 'undefined') { // for Mozilla
		var tarea = document.getElementById(id);
		var selEnd = tarea.selectionEnd;
		var txtLen = tarea.value.length;
		var txtbefore = tarea.value.substring(0,selEnd);
		var txtafter =  tarea.value.substring(selEnd, txtLen);
		var oldScrollTop = tarea.scrollTop;
		tarea.value = txtbefore + what + txtafter;
		tarea.selectionStart = txtbefore.length + what.length;
		tarea.selectionEnd = txtbefore.length + what.length;
		tarea.scrollTop = oldScrollTop;
		tarea.focus();
	} else {
		document.getElementById(id).value += what;
		document.getElementById(id).focus();
	}
}