Useful JavaScript global variables in SharePoint
If you’re using custom JavaScripts with SharePoint 2010 some global JavaScript variables may come in handy. These variables work if you’re using SharePoint’s default or any other custom master page. L_Menu_BaseUrl – the base URL of the site / subsite. Very useful when you need to determine the absolute path of the site in JavaScript. Example: document.location = L_Menu_BaseUrl + ‘lists/calendar/allitems.aspx’ //redirects to Calendar list L_Menu_LCID – the LCID of the site you’re in. Useful if you need to determine the language of the site. The list of Locale IDs can be found here . _spUserId – the ID of the logged in user.