Question

Before diving into code, I’m looking for some good suggestions on how I might go about passing a selected option from a select box to a different php file and then running a specific mySQL query based on the passed option (which option the user selects). Any ideas?

Answer 1

Here is the simplest example to jquery ajax.

Let you aim is to get the cities in a country on select of a country from selectbox, and display the result in a div.

HTML

1. download and include “jquery” to your html page.

2. let this is your selectbox.

   < select name=”country” id=”country”>

   < option value=”1″>Country1< /option>

   < option value=”2″>Country2< /option>

   < /select>

3. Div to display result

   < div id=”city”>< /div>

You should correct the spaces in html code, I put spaces in tags because stackoverflow not showing html code (or I don’t know how to put).

Jquery

<script>
$('#country').live('change', function() {
    $.post("ajax.php",{country_value: $(this).val()},
    function(data){
        $("#city").html(data.cities);
    },"json");
});
</script>

PHP

file >> ajax.php

$country_value = $_POST['country_value'];
$sql = "SELECT `city_name` from `city` WHERE `country_value` = $country_value";
$data = mysql_query($sql);
$output = "";
if($data && mysql_num_rows($data)>0)
{
    while($cities = mysql_fetch_array($data))
    { $output .= $cities['city_name'] .","; }
}
echo json_encode(array("cities"=>$output));