How to use option lists to change POST value ?

Question

I have a gallery page that change the category based on the $_POST("cat"), how do I use the option dropdown list to reload the page (or only the gallery) to change the gallery view accordingly.

Here is the option list:

    <form>
        <select>
        <option value="">Pick A Category:</option>
        <option value="1">Landscape</option>
        <option value="2">Wedding</option>
        <option value="3">Miscellaneous</option>
        </select>
    </form>

Here is the php option list :

 <?php
    $dir_cat[0] = "images/landscape/";
    $dir_cat[1] = "images/wedding/";
    $dir_cat[2] = "images/misc/";
    if (isset($_POST['cat']) && isset($dir_cat[$_POST['cat']])) {
      // alocate image category according to the POST value
      $image_dir = $dir_cat[$_POST['cat']]; 
    } else {
      // set default image category
      $image_dir = $dir_cat[0];
 ?>

Answer 1

in html you can add a value parameter to every option, this will be in the $_POST['cat'] then with a simple 'if' or 'switch' you can change the gallery view

Answer 2

<form action="gallery.php" method= "post">
    <select name="cat" onchange="this.form.submit();">
        <option value="">Select Category:</option>
        <option value="0">Landscape</option>
        <option value="1">Wedding</option>
        <option value="2">Miscellaneous</option>
    </select>
</form>

Answer 3

<form>
    <select id=cat name=cat>
    <option value="0">Pick A Category:</option>
    <option value="1">Landscape</option>
    <option value="2">Wedding</option>
    <option value="3">Miscellaneous</option>
    </select>
</form>

If the form uses the POST method, then you can access the cat like so;

if( isset( $_POST['cat'] ) && (int)$_POST['cat'] < 4 )

All you need to do is then match the value=n in your html form to the key in your $dir_cat[]

$dir_cat[1] = "images/Landscape" ;

Then when you are sure that the incoming 'cat' is within bounds (between 1 and 4) you can just do;

include $dir_cat[$_POST['cat']];