base href needs forward slash at the end

HTML document or iframe head section can  have this tag to specify a default URL and a default target for all links on a page:

<base href="URL" />
<base href="http://www.w3schools.com/images/" target="_blank" />

href for relative paths
target for click link behavior

The URL needs forward slash (/) at the end, otherwise it will not work as expected.

http://www.w3schools.com/tags/tag_base.asp