使用php动态更改选择选项

Okay, so I have this function in PHP that gets an attribute and returns an array. Something like this:

function getProvinces($countryID){
return arrayWithProvinces($countryID);}

Everytime the parent select changes, the function getProvinces() should be executed with the new ID and the arrayWithProvince should be included as options in the child select.

I'm using jquery to handle the events, as I found somewhere. I need to do something like this.

            $("#selectCountry").change(function() {

                var parent = $(this).val(); //get option value from parent 
                var prov = <?php echo json_encode($pagina->getProvinces( <PARENT> )); ?>;
                list(prov);

My problem is that I don't know how to tell the getProvinces($countryID) php function which is the new value of the parent.

Thanks in advance.

As far as I know, you cannot execute the function without reloading entire page (I mean php should recompile it and pass it to the client).

You should use only JavaScript for that purpose. Store you arraylist in JS code, and validate it once upon form submission (just to be sure).

You need to make an Ajax request to the server.

Look at it this way: Your Javascript/jQuery is running on the client side (web browser) and you PHP is running on your web server.

So to communicate between the browser(jQuery) and the server(PHP) you need to make a Ajax request.

jQuery has a ajax function you could use, your best bet is to do some research on the subject as Ajax is something you will use all the time and understanding how it works is crucial.

You should use javascript for that in order to refresh part of your page with dynamic content.Below is an example using jquery's ajax function.When the select with id #parent_select changes you call your php script and you append the returned data (the html of the child select in the example) in a div you want.

Javascript part would be something like this:

$("#parent_select").change(function() {

$.ajax({
    url: "your_script.php?cid="+$(this).val(),
      success: function(html){
        $("#child_select_container").append(html);
      }
    });
});

And your_script.php code would look something like :

<?php
function getProvinces($countryID){
return arrayWithProvinces($countryID);}

$countryID=(int)$_GET['cid'];

$provinces=getProvinces($countryID);

echo '<select id="child_select">';
foreach($provinces as $key=>$province){
echo '<option id="'.$key.'">'.$province.'</option>';
}
echo '</select>;

I havent tested the example.It is just a basic how to example.You should be able to work your way from here.But if you have any problems let me know.