<base>
href   target  

The <base> tag defines a base url and target for the HTML document and is contained in the <head>. The <base> tag is optional.

<base href="">

   Description
   All nonspecific urls such as "images/logo.htm" will be resolved according to the url.
Code
   <base href="URL">

<base target="">

   Description
   Whenever a target is not defined in a <a> tag, the base target is used.
Code
   <base target="DEFAULT_TARGET">
/body>