This is a continuation of the discussion at

http://stackoverflow.com/questions/944158/php-multiple-dropdown-box-form-submit-to-mysql

which ended with the words: "Once you have the variables, it is trivial to create new rows." No doubt that's generally true, but apparently not for this learner...

Given the following form:

    <form action="form.php" method="POST">


    <select name="colors[]" multiple="yes" size="2">


    <option>Red</option>


    <option>Blue</option>


    </select>


    <input type="submit" value="Go!"> 


    </form>

how do I create new rows? The following script

foreach($_POST['colors[]'] as $color) 


    {


        $id = mysqli_real_escape_string($link, $color);


        $sql = "INSERT INTO colors SET id = '$id'";


    }

raises the error

 Warning: Invalid argument supplied for foreach() in form.php on line ...

whereas the following

    $colors = $_POST['colors[]']; 


    for ($i = 0; $i < count($colors); $i++) 


        {


            $color = $colors[$i];


            $sql = "INSERT INTO colors SET id = '$color'";


        }

raises no errors but does no row creation.

What triviality am I missing here?