重定向到索引文件

header('location:index.php');

this redirected to www.website.com/index.php
I want redirect to www.website.com/
So use

header('location:');

But this not work

you may want to use mod_rewrite
something like the in your .htaccess should do the trick

RewriteRule ^a$ about.php

or

    RewriteRule ^a$ about.php&%{QUERY_STRING}

if yo want to keep arguments.
also i don't think you meant to say www.web.com/about .com

u can use this code for .htaccess and for link use www.web.com/about

Options +FollowSymLinks
RewriteEngine on

## handler view
RewriteRule ^about$ about.php [L]