<a href="index.php?autoid='. $autoid .'" class="update" OnClick= "return confirm("do you really want to delete")">DELETE</a></div></td></tr>';
This won't work because the double quotes around the Javascript string literal are confused with the double quotes around the attribute value.
<a href="javascript:cconfirmation(/index.php?deletestu=1&category=STUDENTS&quest=stu&autoid=<? echo $autoid ?>)" class="update">DELETE</a>
This won't work either because now the Javascript string literal isn't quoted at all.
What are you doing to debug?