How to use drop down menu to change PHP object variable?

Question

The title may not be the best way to word this question, so please let me know if I can improve it.

What I am trying to do is use a drop down menu to change the value of a PHP object.

In the example below, I want $selected to be assigned as the "value" of the the menu option selected.

  $selected = $_GET['program_select'];

Here is the drop down menu:

  <select id="programs_select" name="programs_select">
    <option>Select a Different Month</option>  
    <?
     foreach($pagedata->programs as $programs){
    ?>
    <option value="<?=$programs->id?>"><?=$programs->title?></option> 
    <?    
    }
    ?>
  </select>

How can I send this value to the server and reload the page using the selected value?

For example, if the 2nd option is selected and it's id is 2 the result would be:

$selected = 2;

FYI, this is being used to dynamically generate the output data for a thumbnail menu. The "program" being displayed would be determined by the value in the option selected.

Answer 1

  <select id="programs_select" name="programs_select" onchange="ihavechanges(this.options[this.selectedIndex].value)">
    <option>Select a Different Month</option>  
    <?
     foreach($pagedata->programs as $programs){
    ?>
    <option value="<?=$programs->id?>"><?=$programs->title?></option> 
    <?    
    }
    ?>
  </select>
  <script type="text/javascript">
  function ihavechanged(towhat)
     {
     document.location.href = "reload.php?id="+towhat;
     }
   </script>

Answer 2

<select id="programs_select" name="programs_select">
    <option>Select a Different Month</option>  
    <?
    $selected = $_GET['program_select'];
    foreach($pagedata->programs as $programs){
        $seld = ($selected == $program-id) ? 'selected' : '';
        echo '<option value="'.$programs->id.'" '.$seld.'>'.$programs->title.'</option>';     
    }
    ?>
</select>

Answer 3

You are using GET in the php side. So, if you just want to know how to pass the value to your php file, then put your select tag into a form and add a submit button.

<form id="your_id" name="your_id" method="get" action="your_controller/your_function_name">
 <select id="programs_select" name="programs_select">
    <option>Select a Different Month</option>  
    <?
     foreach($pagedata->programs as $programs){
    ?>
    <option value="<?=$programs->id?>"><?=$programs->title?></option> 
    <?    
    }
    ?>
  </select>
  <input type="submit" id="submit" name="submit" value="GO">
</form>

In your controller, echo something based on the value.

$selected = $_GET['program_select'];

However, if your want to change the contents in the same page without refresh. You may need ajax call to do that, and I recommend the jQuery ajax api (http://api.jquery.com/jQuery.ajax/).

$("select#programs_select").live('change', function(){
        var id = $("select#programs_select").val();        
                $.ajax({
                type: "GET",
                url: "your_controller/the_funstion_name?programs_select=" + id,
                data: "",
                contentType: "application/json; charset=utf-8",
                            success: function(msg) {
                $("#your_thumbnail_menu_id").html(msg); 
                },
                error: function() {
                alert("Error! Ajax failed");
                }
            }); 

        });

In your controller side, echo the html you need at last. eg:

$selected = $_GET['program_select']; 
$html = "<ul><li>your menu  $selected</li>";
$html .="<li>which depends on the id you got!</li></ul>";
echo $html;