<form name="s" method="post" action="" >
 <select multiple="multiple" name='problems[]' >
        <option value="Cannot Copy">Cannot Copy</option>
        <option value="Cannot Print">Cannot Print</option>
        <option value="Cannot Print">Cannot Scan</option>
        <option value="Cannot Fax">Cannot Fax</option>
        <option value="Lines Appear When Printing/Copying">Lines Appear When Printing/Copying</option>
        <option value="Scan to Email Failed">Scan to Email Failed</option>
        <option value="Toner Low/Empty">Toner Low/Empty</option>
        <option value="Others">Others</option>
</select>
<input type="submit" name="submit" value="submit" />
</form>


<?php 
if (isset($_REQUEST['submit']) && @$_REQUEST['problems']) {
    $problems =  implode(',', @$_REQUEST['problems']);
    echo $problems;
}
?>