Callback not executing from jQuery post

Question

I'm having problems executing the call back function.

$.post("/" + contentId + "/postComment", {
    "postComment": ""
}, function(data) {
    alert('call back');
});

This post does take place. The alert is not called, however.

This post results in some xml returned. I can't tell exactly how it looks because I'm using Spring mappings of application/xml together with @RequestBody and I just don't know what Spring does to what I'm returning. I'm saying this just in case the contents of server response can affect the call back somehow.

The question is:

what do I need to do to see that alert in my code example?

T.J. Crowder · Accepted Answer · 2012-05-26 16:56:59Z

27

Your code is fine other than that it doesn't hook the error handler (one of the reasons I don't like $.post). I think the POST operation must be resulting in an error. Try converting it to this:

$.ajax({
  type:    "POST",
  url:     "/"+contentId+"/postComment",
  data:    {"postComment":""},
  success: function(data) {
        alert('call back');
  },
  // vvv---- This is the new bit
  error:   function(jqXHR, textStatus, errorThrown) {
        alert("Error, status = " + textStatus + ", " +
              "error thrown: " + errorThrown
        );
  }
});

...so you can see what the error is.

answered May 26, 2012 at 16:56

T.J. Crowder

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4 Comments

Josh Hudnall Over a year ago

+1 because using $.ajax is almost always preferable for exactly the reason you specified.

jacekn Over a year ago

Well, it is alerting 'Error'. Can we get to details of the error, somehow?

T.J. Crowder Over a year ago

@jacekn: You may have seen an earlier copy of the answer; refresh, there's more information available (or refer to the ajax docs). But the best information would come from the browser's debugger. If you're using any modern, quality browser it either has quite a good debugger built in (with network operations listed, including content) or available as an add-on (Firebug, in the case of Firefox). Chrome, Safari, and Opera all have very good ones built in. IE8 and higher have acceptable ones.

jacekn Over a year ago

OK, I see it. Error details give me important info. Thank you, sir!

Constant Meiring · Accepted Answer · 2017-10-02 12:05:37Z

6

Had a similar issue where the callback doesn't fire when you provide a string as data and the server returns a JSON response. To get around this, simply explicitly specify the datatype to be JSON:

function update_qty(variant_id, qty){
  $.post('/cart/update.js', "updates["+variant_id+"]="+qty, function(data){
    updateCartDesc(data);
  }, "json");
}

answered Oct 2, 2017 at 12:05

Constant Meiring

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1 Comment

Luis David Over a year ago

This worked for me and I was sending and object as data.

AgathoSAreS · Accepted Answer · 2018-10-15 17:21:28Z

2

For readability, I would recommend to ignore the above correct answer. As of JQuery 1.5 (or later, and in the questions case) use:

$.post("/" + contentId + "/postComment", {
    "postComment": ""
}).always(function() {
    alert('call back');
});

as stated in the JQuery documentation: https://api.jquery.com/jquery.post/
It's not very clear from the documentation but you get the returned "jqXHR" object from the post request as parameter to the always, fail, and done functions.

You can extend the parameters, as you need, up to:

.always(function(responseArray, request, jqxhr, status, error) {
    alert( jqxhr.responseText );
});

answered Oct 15, 2018 at 17:21

AgathoSAreS

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Comments

dtbarne · Accepted Answer · 2016-11-28 19:54:03Z

0

I noticed that the ajax script needs to have a content-type of application/json rather than application/javascript, if it is indeed JSON.

edited Nov 28, 2016 at 19:54

answered Jan 3, 2015 at 3:08

dtbarne

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3 Comments

Shayne Over a year ago

No, if its a script, its type is application/javascript. application/json is for json. hacking the mime types just undermines the browser document model

dtbarne Over a year ago

@Shayne nobody said it was a script. Come down from that pedestal. :)

Shayne Over a year ago

Well now that you edited your post, sure. But prior to that its pretty much literally what you had said.

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