Send GET Request to HTTP Server; don't care about the response

Question

I'm trying to contact a server using $.get(). I don't care about the response. My purpose is to log some data about a user's action (what they clicked, etc). When the user clicks something, $.get is called like so:

$.get(
        "http://www.some-server.com/log.txt?click=1", 

        function (data)
        {
        },

        "text"
);

The server handles that get request accordingly. I get the following error when the function executes:

XMLHttpRequest cannot load ... is not allowed by Access-Control-Allow-Origin.

If I change datatype to jsonp, I do not get that error but when the jquery callback tries to evaluate the log server's response as JSON, it tells me "whateverwasreturned" is not defined. I'm not able to change anything on the log server.

Does the server return any data? You said that you don't care about the response..its a bit confusing what your goal is here. — Sean Thoman, Nov 04 '11 at 20:59
have you seen this question http://stackoverflow.com/questions/3595515/xmlhttprequest-error-origin-null-is-not-allowed-by-access-control-allow-origin — Nathan, Nov 04 '11 at 21:01

score 6 · Accepted Answer · answered Nov 04 '11 at 21:00

6

Use a "tracking pixel" technique instead:

<img src="http://www.some-server.com/log.txt?click=1" height="1" width="1">

Just insert the HTML into the DOM when needed.

answered Nov 04 '11 at 21:00

Diodeus - James MacFarlane

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1

Make sure you check if your page handles https, you need to change the src attr to https as well (if only the site has ssl) – ysrb Nov 04 '11 at 21:03
I'm using the method $("body").append("") and am seeing the ping go out in wireshark for the first action, but not any subsequent actions. – SemperFly Nov 04 '11 at 21:28
1

You need to "salt" the URL to break the cache. Use ?click=1&now="+new Date() – Diodeus - James MacFarlane Nov 06 '11 at 16:04
Why append to dom? Why not create element in memory set src to send request, then exit function? – Joshua Robinson Jul 27 '17 at 18:46

score 1 · Answer 2 · answered Nov 04 '11 at 21:02

1

If you're using jquery, just add a script tag to avoid the same-origin-policy problem:

$('body').append('<script src="http://www.some-server.com/log.txt?click=1"></script>');

answered Nov 04 '11 at 21:02

Alex Schenkel

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score 0 · Answer 3 · answered Nov 04 '11 at 21:01

Not sure if you'll be able to... if you were talking to your own server, then it'd be simple to tell JS to treat the response as plaintext and not try to decode it. But once you're doing JSONP, then jquery is really just building a <script src="http://otherserver.com"></script> block and inserting it, means which means the remote server must reponse with valid JS code.

One alternative would be to load an image containing your json p url. The image itself would be "broken", but would still trigger a GET request.

score 0 · Answer 4 · answered Nov 04 '11 at 21:03

Becouse of same origin policy you cannot send ajax query to other domain (then script executes) but as you discover you can use jsonp but only when server support it (server basicly waraps JSON) and there is method for that $.getJson(..) it's easier way to call $.ajax(..)

http://api.jquery.com/jQuery.getJSON/

example of server side (in php) that supports jsonp: http://www.geekality.net/2010/06/27/php-how-to-easily-provide-json-and-jsonp/

score 0 · Answer 5 · answered Nov 04 '11 at 21:04

0

You can keep using JSONP, but make your log.txt return an empty JSON object: {}.

answered Nov 04 '11 at 21:04

Oleg Grishko

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score 0 · Answer 6 · answered Nov 04 '11 at 21:08

0

You can use the pure ajax call:

$.ajax({
  url: 'http://www.some-server.com/log.txt?click=1',
  dataType: 'jsonp',
  crossDomain: true,
  success: function(data) { /* do nothing */ }
});

answered Nov 04 '11 at 21:08

sethvargo

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Thanks for the response. This still causes the "returned" is not defined error. – SemperFly Nov 04 '11 at 21:10

Send GET Request to HTTP Server; don't care about the response

6 Answers6