jquery - Post form input to PHP using AJAX for multiple autocomplete query conditions

I'm using jquery autocomplete on an input form 'city' but i would like the query in my 'autocity.php' file to only suggest cities in the pre selected country i.e. WHERE City LIKE '%$term%'" AND CountryID = '%$country%'. The form action submit uses a separate PHP file (create-business.php) for inserting the form data to the database so the usual $_POST['Countries_CountryId'] wouldn't work in the autocity.php. that's why i'm now using AJAX to post 'country' to autocity.php. Also it would be great to have a way to echo/alert/print_r from the the autocity.php file so i can confirm that the $_POST['$country'] from the ajax post reaches the autocity.php file.

I have two input boxes in the form

`



`

Here is the script from the form

And here is autocity.php

`

//database connection works fine and autocomplete 
//suggestion works without the AND CountryID = '%$country%' part.  

    $country = "";
    if (isset($_POST['country'])) {
    $country = trim($_POST['country']);}
    echo "window.alert($country);"; //This did nothing no alert

    $term = $_REQUEST['term'];
    $req = "SELECT City

            FROM cities
            WHERE City LIKE '%$term%' AND CountryID = '%$country%'";

    $query = mysql_query($req);
    while ($row = mysql_fetch_array($query)) {
        $results[] = array('label' => $row['City']);
    }
    echo json_encode($results);
    ?>`
    

So the question is basically:

1 - how can i use a text input from a form using AJAX in a .php file that queries a MySQL db that is not the submit form action .php file

2 - how can i alert the post variable from the PHP file when ajax is used to show that the php file recieves my ajax post. In my brief experience echo and print_r only work on form submit when the web page changes showing the result of my form submit ont the form action.

3- how is my syntax?

Thank you very much in advance for helping this novice out :D

---

Ok here is my update on things i've tried. I think i'm close. i'm using Jquery UI -
//ajax.googleapis.com/ajax/libs/jqueryui/1.10.0/jquery-ui.min.js

here is the script method 1:

   $(document).ready(function () {
    var country = $('#country').value();

    alert(country + " complete");
    $("#city").autocomplete(
          {
            source:'autocomplete/autocity.php?country='+country,
            minLength:1
           });
        });

here is the script method 2:

 $(document).ready(function () {

    $('#city').autocomplete({
        // source: function() { return "GetState.php?country=" + $('#Country').val();},
        source:function (request, response) {
            $.ajax({
                url:"autocomplete/autocity.php",
                //dataType:"json",
                data:{

                    term:request.term,
                    country:$('#country').val()
                },
                success:function (data) {
                    response(data);
                }
            });
        },
        minLength:2
    });

  });

I like method 2 more since it will allow me to add more than one parameter.

Finally here is my latest autocity.php code

     $term = $_REQUEST['term'];
    $country = $_REQUEST['country'];

    $req = "SELECT City
    FROM cities
    WHERE City LIKE '%$term%' AND CountryID = '%$country%' ";

    $query = mysql_query($req);

    while ($row = mysql_fetch_array($query)) {
    $results[] = array('label' => $row['City']);
    }


    echo json_encode($results);
     ?>

I'm still totally stuck though. can anybody see the problem with the code? Ive looked everywhere online for the right syntax. Thanks again

Answer

For the first problem, your approach is essentially correct. You can bind to the blur event for a particular field and use your function to get that field's value and submit to the php script much in the manner that you are doing so. $.blur() is what you're looking for.

For the second problem the error_log function will write stuff to php's error log. IF you use print_r to dump variables to this log, make sure to set print_r's second argument to true to output the result as the return value.