How does the “a” tag in html work with path levels

[sagito3x]

I have this current URL for example \[code\]http://test.com/dir1/dir2/dir3/div4\[/code\], on this page i want a link that just adds /dir5 to the current tag so I will get \[code\]http://test.com/dir1/dir2/dir3/div4/dir5\[/code\]. I know you can use \[code\]<a href="http://stackoverflow.com/dir5">dir5</a> or <a href="http://stackoverflow.com/questions/14431162/dir5">dir5</a>\[/code\]But these results are different a lot depending on the current URL path and sometimes doesn't make any sence to me. Is there a way I can easily add another directory to the path in the \[code\]<a>\[/code\] tag or would I just have to write the full path name down in the \[code\]<a>\[/code\] tag?