Display different dive when select different select option with MySQL query - php

Question

There are some table in my DB. In "level" table, there are 3 level, "O level", "A level" and "Another level". And I have 3 subject table for these level. They are "sub_o", "sub_a" and "sub_another" and they have different subjects. I make a select option for "level" table by SQL query.
Code is given below:
<select name="" id="">
<?php
$result = mysql_query("SELECT * FROM vhlabel");
while($row = mysql_fetch_array($result))
{
echo "<option>".$row['label_name']."</option>";
?>
</select>
And there are different subject for different level. I want when I will select "O level", then its subject will be displayed in check box. And when I select another level, another subjects will be displayed in check box.

Answer 1

What you want can easily be achieved with AJAX and by using jQuery the AJAX becomes more easier. So your solution with that can somehow be as below:
<select name="level" id="level">
<?php
$result = mysql_query("SELECT * FROM vhlabel");
while($row = mysql_fetch_array($result))
{
echo "<option>".$row['label_name']."</option>";
?>
</select>
<div id="sub">
</div>
<script>
$('#level').on('change', function() {
var levelChangedTo = $(this).val();
//AJAX request to some server script that will pass the changed level
//And that script would return the HTML that would be appended
//to some other div which would have checkboxes.
$.ajax({
method: "POST",
url: "serverside.php",
data: { selectedLevel: levelChangedTo }
})
.done(function( response ) {
//Here append or replace the HTML according to your needs
jQuery('#sub').append(response);
});
});
</script>
Note: This is just a guideline through which you can achieve your goal.