dependent dropdown list

[scmeeker]

I'm trying to create a dependent drop down list.  If a user picks something from the initial category list, I want the subcategory list to change to populate with its relevant category ID.  Kind of like picking a state from the first drop down then the next would populate with all the state's cities.

 

When I print this, it lists individual drop down lists rather than one.  Is there another way I should be looking at this?

 

Thanks for your suggestions.

 

  //Set the selected category
$selected_cat = (isset($_GET["cat_id"])) ? $_GET["cat_id"] : false;

//show categories first
$result = mysql_query("SELECT cat_id, cat_title FROM category ORDER BY cat_id")
or die(mysql_error());

if (mysql_num_rows($result) < 1)
{
   $categoryList = "<p><em>Sorry, no categories to browse.</em></p>";
}
else
{
    //Display the categories
    while ($cats = mysql_fetch_array($result))
    {
	$cat_id = $cats['cat_id'];
	$cat_title = $cats['cat_title'];

        $categoryList .= "<select name=\"cat_id\" class=\"blackfont\">
    <option value=$cat_id>$cat_title</option></select>";

		        if ($cats['cat_id']==$selected_cat)
        {
            //get items
            $get_items_sql = mysql_query("SELECT id, cat_id, sub_title FROM sub_category WHERE cat_id = '{$selected_cat}'")
		or die(mysql_error());
            
            if (mysql_num_rows($get_items_sql) < 1)
            {
                $content = "<p><em>Sorry, no items in this category.</em></p>\n";
            }
            else
            {
                
                while ($items = mysql_fetch_array($get_items_sql))
                {
                 $cat_id = $cats['cat_id'];
			 $sub_title = $cats['sub_title'];  

			 $content .= "<select name=\"sub_id\" class=\"blackfont\">
    <option value=$cat_id>$sub_title</option></select>";
            }

[Psycho]

Not tested, so there may be some syntax errors

//Run query to get categories
$query = "SELECT cat_id, cat_title FROM category ORDER BY cat_id";
$result = mysql_query($query) or die(mysql_error());
    
if (!mysql_num_rows($result))
{
    $categoryList = "<p><em>Sorry, no categories to browse.</em></p>";
}
else
{
    //Set the selected category (if exist)
    $selected_cat = (isset($_GET["cat_id"])) ? $_GET["cat_id"] : false;

    //Create category select list
    $categoryList = "<select name=\"cat_id\" class=\"blackfont\">\n";
    //Display the categories
    while ($cats = mysql_fetch_array($result))
    {
        $selected = ($cats['cat_id']==$selected_cat) ? ' selected="selected"' : '';
        $categoryList .= "<option value=\"{$cats['cat_id']}\"{$selected}>{$cats['cat_title']}</option>\n";
        //Set first category as selected if none selected, so we can determine subcategories to display
        if($selected_cat===false) { $selected_cat = $cats['cat_id']; }
    }
    $categoryList .= "</select>\n";
    
    //Run query to get subcategories
    $query = "SELECT id, cat_id, sub_title FROM sub_category WHERE cat_id = '{$selected_cat}'";
    $result = mysql_query($query) or die(mysql_error());

    if (!mysql_num_rows($result))
    {
        $subCategoryList = "<p><em>Sorry, no categories to browse.</em></p>";
    }
    else
    {
        //Create subcategory select list (if needed)
        $subCategoryList = "<select name=\"sub_id\" class=\"blackfont\">\n";
        while ($subcats = mysql_fetch_array($result))
        {
            $subCategoryList .= "<option value=\"{$subcats['cat_id']}\">{$subcats['sub_title']}</option>\n";
        }
        $subCategoryList .= "</select>\n";
    }

}