Here is some sample code: 

while(document.getElementById('zz2_QuickLaunchMenu'+i) != null)
                          { //&& i < divsArray.length){
                            var menu = document.getElementById('zz2_QuickLaunchMenu'+i);
                            var hyperlinks = menu.getElementsByTagName('a');  //looks for the hyperlink tags using the quicklaunch tag

                                hyperlinks[0].href = hyperlinks[0].href.replace(URL, URLToReplace);  //replaces the URL text
                                hyperlinks[0].target = "_blank";                            //allows for opening the link in a new window  
                       
                                   
                            i+=1;
                        }
This tag for the quicklaunch: zz2_QuickLaunchMenu you can find by right clicking on your list and looking for the quick launch menu.  It will probably include the name "QuickLaunchMenu" and some text in the same format as zz2_.  The code is pretty straightforward.  If you have any comments or questions let me know.  Have a very good weekend!