How can I display a separate block depending on the selected name in the drop-down list?

Question

PHP

There is a page where there is, let's say there are 4 names in the "select" to choose from. Depending on the selected name, a specific block should be displayed.
Wrote the following code:

<?php 
        $elegant = file_get_contents('./tarifs/elegant.php');
        $myRules = file_get_contents('./tarifs/myRules.php');
        $noDamage = file_get_contents('./tarifs/noDamage.php');
        $canAll = file_get_contents('./tarifs/canAll.php');
        $none = file_get_contents('./tarifs/none.php');
 
        $values=array("Выберите нужный вам тариф..","Элегантный","Несокрушимый","Можно все", "Свои правила");
        
        $number=count($values);
    ?>
    <form method="post">
        <select name="polling" class="hover">     
    <? for($i=0; $i<$number; $i++) echo "<option value=\"$i\"> $values[$i]</option>"; ?></select><br><br>
        <li><input type="submit" value="Показать" class="hover"/></li>
        </form>
 
 	<? if($_POST=1){
   echo $elegant;
  }else{
   if ($_POST=2){
   echo $noDamage;
  }else{
  }if ($_POST=3){
   echo $canAll;
  }else{if ($_POST=4){
   echo $myRules;
  }else{if ($_POST=0){
   echo $nones;
  }}}}
  ?>

Where it turns out that by selecting and clicking on the "Show" button, certain blocks are displayed below, depending on the selected name, where 0 is "Select the tariff you need .." and when you select it, nothing is shown and where subsequent names have their own number .
It is written below that if "Post" has a value of 1, then one is displayed, otherwise the subsequent calculations take place.
But all this did not work as I thought, and instead of displaying the selected one, it always displayed the very first stage.
Then I tried to replace the previous calculation with this code:

<? if($_POST=1){
   echo $elegant;}?>
  <? if ($_POST=2){
   echo $noDamage;}?>
  <? if ($_POST=3){
   echo $canAll;}?>
  <? if ($_POST=4){
   echo $myRules;}?>
  <? if ($_POST=0){
   echo $none;}?>

After that, I received the output of absolutely all blocks.
How can this be fixed and where is the fatal error here or how is it better

Answer 1

You are comparing a superglobal variable $_POSTwith a number: , there are several errors: 1) the comparison is done using a double equals sign 2) comparison with a number does not make sense, because is an array, not a number. It is necessary to compare like this: 3) Brackets are not correctly placed through if / else constructions, all the logic is broken there (although purely by chance everything turned out to be syntactically correct) if($_POST=1)