Question

I want to display posts for multiple categories. I have created a MULTISELECT drop down of all categories using code below:

<form method="get" action="<?php bloginfo('home');?>" >
    <select name="cat" multiple> 
     <option value=""><?php echo esc_attr(__('Please Select Your Choice')); ?></option> 
     <?php 
      $categories=  get_categories('show_count=0&orderby=name&echo=0&hierarchical=true&depth=1&taxonomy=category&exclude=1'); 
      foreach ($categories as $category) {

        $option = "<option value=$category->term_id>";
        $option .= ucfirst($category->cat_name);
        $option .= '</option>';
        echo $option;
      }
     ?>
    </select>
<input type="submit" id="searchsubmit" value="Search" name="submit"/>   
</form>

Whenever i selects more than one category, I can see all cat ids in url like: http://abcd.com/?cat=7&cat=8&cat=9 But it displays only last category posts using archieve.php file. I want to display all selected category posts on the page.

Thanks in advance.

Answer 1

<?php 
if(isset($_POST['submit']))
{
    $categories = $_POST['category'];

    print_r($categories);   
}
?>
<form action="" method="post">
    <select name="category[]" size="5" multiple="multiple">
        <option value="1">Red</option>
        <option value="2">Green</option>
        <option value="3">Blue</option>
        <option value="4">Yellow</option>
        <option value="5">Orange</option>
        <option value="6">Purple</option>
        <option value="7">Megento</option>
        <option value="8">Green</option>
        <option value="9">White</option>
        <option value="10">Black</option>
    </select>
    <input type="submit" name="submit" value="Submit" />
</form>

Note use of [] in here –