<script>        
        function savesel(doc)
        {
                if(document.selection) {                
                        doc.sel = document.selection.createRange().duplicate();
                }               
        }
        function click_bb(aid,Tag) {
                var Open='['+Tag+']';
                var Close='[/'+Tag+']';
                var doc = document.getElementById(aid);
                doc.focus();
                if (window.attachEvent && navigator.userAgent.indexOf('Opera') === -1) {                                        
                        var s = doc.sel;
                        if(s){                                  
                                var l = s.text.length;
                                s.text = Open + s.text + Close;
                                s.moveEnd("character", -Close.length);
                                s.moveStart("character", -l);                                           
                                s.select();                
                        }
                }   else {                                              
                        var ss = doc.scrollTop;
                        sel1 = doc.value.substr(0, doc.selectionStart);
                        sel2 = doc.value.substr(doc.selectionEnd);
                        sel = doc.value.substr(doc.selectionStart, doc.selectionEnd - doc.selectionStart);                                              
                        doc.value = sel1 + Open + sel + Close + sel2;
                        doc.selectionStart = sel1.length + Open.length;
                        doc.selectionEnd = doc.selectionStart + sel.length;
                        doc.scrollTop = ss;                                             
                }
                return false;
        }
</script>
 
<form name="form_name">
<div onclick="click_bb('area_id', 'b');">BB - 1</div>
<textarea id="area_id" cols="40" rows="4" onselect='savesel(this)' onchange='savesel(this)' onclick='savesel(this)' onfocus='savesel(this)' onkeyup='savesel(this)'></textarea>
</form>