Question

I asked this question previously but i think i made it too complex, I want to assign a query if a value from a list is selected.

<form id="filter" name="filter" method="post" action="">
<select>
  <option value="petrol">Petrol</option>
  <option value="diesel">Diesel</option>
</select>
<p><input name="filter" type="button" value="Filter" /></p>
</form>

What i want to achieve is if user selects petrol the run the following query

$query = mysql_query("SELECT fuel_type from car WHERE fuel_type = 'petrol'");

Answer 1

<form id="filter" name="filter" method="post" action="">
<select id="college" name="fuel" onchange="changeValue();">
  <option value="petrol">Petrol</option>
  <option value="diesel">Diesel</option>
</select>
<p><input name="filter" type="button" value="Filter" /></p>
</form>

If you want to post the value in form submit use like this

$ctext = $_POST['fuel']; 
$list = mysql_query("SELECT fuel_type from car WHERE fuel_type ='$ctext'");
$row = mysql_fetch_array($list);
//process $row

If you don’t want to submit the form, you can use jquery in onchange event…
js code

<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript">
function changeValue() {
    var ctext = $("#college option:selected").val();
    $.ajax({ url: "yourfile.php", 
    data: {"ctext":ctext},
    type: 'post',
    success: function(output) {
        //display output here
      }
    });
}

yourfile.php

<?php
//connect to db
$ctext = $_POST['ctext'];
$list = mysql_query("SELECT fuel_type from car WHERE fuel_type ='$ctext'");
$row = mysql_fetch_array($list);
echo $row['fuel_type'];
?>