How to work this if condition in form and codeigniter - php

Question

i am using this condition for check box value in codeigniter i want if $v_d value take go in 3rd condition ,and value $v_v then go in 2nd condition and if avail both value then go 1st condition.
print_r($this->input->post());
$id =$this->input->post('id');
$v_v=$this->input->post('d_v');
$v_d=$this->input->post('d_d');
if(isset($v_d) && isset($v_v)){
echo"hwqq";
}
elseif(isset($v_v)){
echo"hello1";
}
elseif(isset($v_d)){
echo"he2";
}
HTML CODE iS THIS
<form action="<?php base_url()?>index.php/index/home_email_update" method="POST">
<input type="hidden" name="id" value="<?php echo $id; ?>"/>
<h5><?php echo $msg;?></h5>
<?php if($f['subscription_discount_voucher']== 1){?>
<div class="email"><input type="checkbox" name="d_v" value="0" id="textfield"> Unsubscribe from Discount Voucher Emails.</div>
<?php }else{?>
<div class="email"><input type="checkbox" name="d_v" value="1" id="textfield"> Subscribe from Discount Voucher Emails.</div>
<?php }
if($f['subscribe_daily_deal']==1){ ?>
<div class="email"><input type="checkbox" name="d_d" value="0" id="textfield"> Unsubscribe from Daily Deal Emails. </div>
<?php } else{?>
<div class="email"><input type="checkbox" name="d_d" value="1" id="textfield"> Subscribe from Daily Deal Emails. </div>
<?php }?>
<div class="email_1"><button type="submit" class="submit_new">Change</button></div>
</form>

Answer 1

Try this,
$id =$this->input->post('id');
$v_v=$this->input->post('d_v');
$v_d=$this->input->post('d_d');
if(isset($v_d) && !isset($v_v)){
echo "hwqq";
}
else if(!isset($v_d) && isset($v_v)){
echo "hello1"
}
else if(isset($v_d) && isset($v_v)){
echo "he2";
}

Answer 2

Since $this->input->post() returns FALSE if there aren't any matches in the $_POST superglobal, isset check is not going to be an appropriate check here.
Instead you could try using empty:
if(!empty($v_d) && !empty($v_v)){
echo"hwqq";
}
elseif(!empty($v_v)){
echo"hello1";
}
elseif(!empty($v_d)){
echo"he2";
}
Please make sure to check Return values of empty for the list of things considered empty.