从克隆表单php保存数据

my form i have a form, where user and more requirement. but while saving only the first input value is being saved.the requirementID, requirement and requirementType are the data that should be saved more than 1 time, but it is not.

// Values to insert
                    $requirementID=0;
                    $functionName=$_POST ["functionName"];
                    $requirement = $_POST["requirement"];
                    $requirementType = $_POST["requirementType"];


$sql = "INSERT INTO requirements (requirementID,requirement,       functionID,requirementTypeID) VALUES 
                        ('$requirementID', '$requirement','$functionName',' $requirementType')";
$result = mysql_query( $sql,$conn );
 }