Javascript Variable to PHP via AJAX (GET Method)

Question

I am trying to pass a Javascript variable to a PHP file using AJAX.

I have the below Javascript code;

<script type="text/javascript">
var route_id = 'travelling-from'; //Route ID

$('#'+route_id).change(function(e) {
    //Grab the chosen value on route change
    var selectroute = $(this).val();

    $.ajax({
        type: "GET",
        url: 'ajax-getvalues.php',
        data: { selectroute : selectroute }
    });
});
</script>

In my ajax-getvalues.php, I have;

$selectroute = mysqli_real_escape_string($connection, $_GET['travelling-from']);

When I try to use $selectroute, it seems to be empty.

Do I need to add something else in order for this to work? Or have I gone wrong at some point?

selectroute is the name that you're sending not travelling-from — Musa
– Musa, Commented Mar 11, 2015 at 16:43
also GET should be used to get data, use POST to send data. — LJᛃ
– LJᛃ, Commented Mar 11, 2015 at 16:53
POST should be used when the client is sending data that will change the server's state (like a database update). GET may or may not be appropriate here as we have no idea what ajax-getvalues.php does. — robbmj
– robbmj, Commented Mar 11, 2015 at 16:57
@robbmj you're right, I somehow was assuming this would update session data but it may aswell be a simple search query. — LJᛃ
– LJᛃ, Commented Mar 12, 2015 at 1:34

robbmj · Accepted Answer · 2015-03-13 20:23:40Z

3

When I try to use $selectroute, it seems to be empty

The AJAX request will be sent to ajax-getvalues.php with the query string:

?selectroute=somevalue

In PHP you are trying the get the value of a parameter called travelling-from, this parameter does not exist in the query string.

You need to change selectroute to travelling-from

$.ajax({
    type: "GET",
    url: 'ajax-getvalues.php?travelling-from=' + encodeURIComponent(selectroute)
});

Or of you prefer:

$.ajax({
    type: "GET",
    url: 'ajax-getvalues.php',
    data: {"travelling-from": encodeURIComponent(selectroute)}
});

This produces the query string ?travelling-from=somevalue which can now be accessed with $_GET['travelling-from']

edited Mar 13, 2015 at 20:23

answered Mar 11, 2015 at 16:46

robbmj

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9 Comments

Sarah92 Over a year ago

Thanks for your suggestion, I added in the encodeURIComponent and I thought this had solved it but I am still having the same issue - it seems the selection value is being sent but not received by the PHP file - that is my guess anyway..?

robbmj Over a year ago

@Sarah92 my answer addressed your original question (why you couldn't get the value of travelling-from in PHP). Since then you have modified the question such that you are not asking the same question any more. I suggest that you roll-back to the original question and start a new one for this new issue.

robbmj Over a year ago

@Sarah92, you should undo the edit you made a few minutes ago as well.

Sarah92 Over a year ago

how do I undo my edit as I do not have the original code I posted anymore?

robbmj Over a year ago

@Sarah92, you can view the edit history and copy and paste from the previous version.

|

SGD · Accepted Answer · 2015-03-13 20:15:51Z

0

In your example the key should be route_id instead of selectroute

<script type="text/javascript">
var route_id = 'travelling-from'; //Route ID

$('#'+route_id).change(function(e) { //Grab the chosen value on route change var selectroute = $(this).val();

var data = {};
data[route_id] = selectroute;
$.ajax({
                type: "GET",
                url: 'ajax-getvalues.php',
                data: data }
            }); </script>

edited Mar 13, 2015 at 20:15

answered Mar 11, 2015 at 16:52

SGD

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4 Comments

Sarah92 Over a year ago

Thanks for your response - I tried this suggestion and had no luck. It seems the value is being sent but not received in the PHP file...:(

SGD Over a year ago

That's weird, just to be sure, you verified via console that that AJAX request is correct, right? But $_GET['travelling-from'] should then do the trick on the PHP side of things. Is there any proxy or something in between which might swallow the HTTP param?

robbmj Over a year ago

Your solution plainly does not work route_id is interpreted literally as the value route_id which would create a query string in the form of ajax-getvalues.php?route_id=somevalue

SGD Over a year ago

Haha, you are of course right. I'll update the example.

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