Question

I’m currently faced with a dilemma. I’m trying to build a menu that will display an array of data from a database. The user will then select an item from that list, and based on this, I need to make a database call to retrieve that data associated with that. Here is the current code that I have.

function foobar() {
  $first_option_sql = "SELECT * from {location} l ORDER BY name ASC";
  $list_first_option = db_query($first_option_sql);

  $output .= "<p><b>Please select the primary location that you would like to check.</b><p>"
  $output .= "<br><b>Location: </b> <select id='list'><option>Available locations</option>";

  while($first_option_available = db_fetch_object($list_first_option)){
    $output .="<option locationid='$first_option_available->lid'>".$first_option_available->name."</option>";
  }

  $output .="</select><input type=submit value='Search'>";
  $output .="<p><b>Children: </b><select id='child'><option selected='yes'>Available children</option><p>";

  $children_available_sql = "SELECT complexquery WHERE lid='%d' ORDER BY l.name ASC";
  $list_children = db_query($children_available_sql);

  while($children_available = db_fetcj_object($list_children)){
    $output .="<option>".$children_available->name."</option>";
  }

  return $output;

}

The problem here is that using this code, am unable to retrieve the value of the selected “first option”, thus the second query never actually taking place; this does not populate the second list.

I was thinking of using AJAX or Javascript, but I’m not too familiar with either. Therefore, I wanted some insight as to how I may be able to perform this.

Answer 1

First off, your HTML is invalid or simply missing details.

You need a name element for your select box:

<select name="lid" id='list'>

locationid won’t work when submitting a form:

<option locationid='$first_option_available->lid'>

You need a value attribute instead:

<option value='$first_option_available->lid'>

With the proper HTML, $_POST[‘lid’] will be the location id that you want. You can pass this to your function:

$menu = foobar($_POST['lid']);

function foobar($lid) {
    //...
}