Why a function checking if a string is empty always returns true? [closed]

Answer 1

if you have a field namely serial_number and want to check empty then

$serial_number = trim($_POST[serial_number]);
$q="select * from product where user_id='$_SESSION[id]'";
$rs=mysql_query($q);
while($row=mysql_fetch_assoc($rs)){
if(empty($_POST['irons'])){
$irons=$row['product1'];
}

in this way you can chek all the fileds in the loop with another empty function