Can anyone tell me if there is any error in the code. Because I think that $ _POST is not properly defined, because it didn't skips the first IF even when there is some value

PHP Code:
for($i=1$i<=15$i++) {
$hbs "other_text".$i;

if(
$_POST['other_text'.$i]]=="") { 
echo 
"You didn't eneter quantity"
die(); 
}

if(!
is_int($_POST['other_text'.$i]) || isset($_POST['vin'.$i])) {
$vins .= '<tr><td>'.$_POS['vin_lbl'.$i].'</td><td…
}
else {
echo "Incorrect data for quantity. \n Please go back.";
}

Now show me that Undefined index: other_text1 so i checked the form in html and this is the code of the textbox
HTML Code:
<input type="text" value="1" disabled name="other_text1" style="width:15px; padding:1px; height:10px; font-size:9px; background-color:#FFF; box-shadow:none; ">
and this is my declaration of the form
HTML Code:
<form name="f1" action="env.php" method="post">