I'm using the following form as part of an Advanced Search page on my WordPress install.

```
<form action="/advanced-search/" method="get">

```

The form is working correctly, but producing URLs like:

`/advanced-search/page/3/?act=s&f=cichlidae&g&s&c&r&tmin&tmax&hmin&hmax&pHmin&pHmax&cmin&cmax&sF&sM&aL&aD&aH`

Is there any way to stop the form from sending those empty variables? In the above example only `f` was searched for (value `cichlidae`). As such I'd prefer it to produce a URL like this:

`/advanced-search/?act=s&f=cichlidae` (plus the `/page/3/` if necessary).

I can't use `$_POST` because I can't get the WordPress `paged` variable to work with `$_POST` values.

Thanks in advance,