How Can I Create a Search Form That Searches by Category Type?

In order to add a function to your search that allows it to perform by Category Type, you should add this line into your form code just after the text input field where the customer is to enter search text:

<select name="searchby_category">AUTO_GENERATED_OPTIONS_CATEGORYTYPES</select>
So an example Search Form that operates by Category Type would look something like this, in proper SearchFit code:
<form style="margin:0px" action="tool_dynamic.php" method="post">
          <input type="hidden" name="action" value="search">
          <input type="hidden" name="searchby1" value="keywords">
          <input type="hidden" name="searchby2" value="categorytype">
          Search for <input type="text" class="text" name="searchby_keywords" value="" size="15">
          In <select name="searchby_category">AUTO_GENERATED_OPTIONS_CATEGORYTYPES</select>
          <input type="submit" class="btn" name="submitit" value="Search">
    </form>