Specify a default URL and a default target for all links on a page
JavaScript:
//http://www.w3schools.com/tags/tag_base.asp
<head>
<base href="http://www.w3schools.com/images/" target="_blank">
</head>
<body>
[img]stickman.gif[/img]
[url='http://www.w3schools.com']W3Schools[/url]
</body>