U.Helper

function get_selection(){if(document.getSelection){selection=document.getSelection()}else if(window.getSelection){selection=window.getSelection().toString()}else if(document.selection){selection=document.selection.createRange().text}}

function Insert(qname,text){if (text!=""){ qname=qname.replace(/[\[\]]/g, "|");  paste("[quote="+qname+"]"+text+"[/quote]\n", 0);} else {_uWnd.alert('Выделите текст для цитирования','',{w:230,h:80,tm:3000});}}  
function paste(text,flag){if ((document.selection)&&(flag)) {document.addform.message.focus();document.addform.document.selection.createRange().text = text;} else document.addform.message.value += text;}
function get_selection(){if(document.getSelection){selection=document.getSelection()}else if(window.getSelection){selection=window.getSelection().toString()}else if(document.selection){selection=document.selection.createRange().text}}

<a href="javascript://" onclick="Insert('$USERNAME$',selection);" onmouseover="get_selection()">Цитировать</a>

[quote=someuser][object Selection][/quote]

javascript:alert(selection)

javascript:alert(document.selection)

[object Selection]