Uncaught SyntaxError: Unexpected token :

Question

I am running an AJAX call in my MooTools script, this works fine in Firefox but in Chrome I am getting a Uncaught SyntaxError: Unexpected token : error, I cannot determine why. Commenting out code to determine where the bad code is yields nothing, I am thinking it may be a problem with the JSON being returned. Checking in the console I see the JSON returned is this:

{"votes":47,"totalvotes":90}

I don't see any problems with it, why would this error occur?

vote.each(function(e){
  e.set('send', {
    onRequest : function(){
      spinner.show();
    },
    onComplete : function(){
      spinner.hide();
    },
    onSuccess : function(resp){
      var j = JSON.decode(resp);
      if (!j) return false;
      var restaurant = e.getParent('.restaurant');
      restaurant.getElements('.votes')[0].set('html', j.votes + " vote(s)");
      $$('#restaurants .restaurant').pop().set('html', "Total Votes: " + j.totalvotes);
      buildRestaurantGraphs();
    }
  });

  e.addEvent('submit', function(e){
    e.stop();
    this.send();
  });
});

The JSON is fine. The problem is probably how you handle it. Showing the code will help. — tcooc, Jun 29 '10 at 18:42
There doesn't seem to be anything wrong with the syntax, the JS nor JSON. Posting a (not)working test-case on jsfiddle.net would help - including HTML. — Oskar Krawczyk, Jun 29 '10 at 19:23
You can check the site that is causing problems here: http://trobrock.com:8011 click on "Cat 1" and then the problem happens when clicking vote, and have only seen the problem in chrome so far — trobrock, Jun 29 '10 at 20:45
I'm currently tethering internet so my modem compresses the HTML source of the websites I browse, so I can't really make heads or tails out of the code. But, for starters put every JS code in external files - this always makes debugging easier - you'll know weather the error is caused by JS or something else. — Oskar Krawczyk, Jun 29 '10 at 22:43
An "unexpected token" is likely some illegal character code. Such a code is likely not to show up when you print to console. Therefore, print out the string one character at a time or use a protocol analyzer or debugger etc. to see the actual bytes of the string. — GroovyDotCom, Feb 10 '11 at 22:00

score 113 · Answer 1 · edited Dec 29 '19 at 04:35

113

Seeing red errors

Uncaught SyntaxError: Unexpected token <

in your Chrome developer's console tab is an indication of HTML in the response body.

What you're actually seeing is your browser's reaction to the unexpected top line <!DOCTYPE html> from the server.

edited Dec 29 '19 at 04:35

miken32

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answered Oct 28 '14 at 17:56

andy magoon

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I have no idea why you are talking about "Unexpected token – Michał Perłakowski Dec 29 '15 at 14:41
2

And how do I fix this? I have a php redirect that is causing this in Chrome. – Works for a Living Mar 08 '16 at 20:20
10

To add to @andy_magoon, in my case, I had a script tag that was supposed to serve up javascript, but because the request was redirected to an HTML page (its not important why it was redirected), which begins with , which is not valid javascript, the browser returns the SyntaxError when it attempt to parse the HTML as JS. – david.barkhuizen Apr 04 '16 at 10:54
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@Thom The way to fix it is to make sure that the HTTP get returns the javascript file that you're looking for, and not unexpected HTML. – david.barkhuizen Apr 04 '16 at 11:07
1

I got exactly this error because, as it turns out, the file path is incorrect and it can't find the file specified in script tag. – newman Jan 25 '17 at 01:57
mine was `301 redirect` issue itself. Fixed by appending `/` at the end of url. – Kishor Pawar Aug 02 '17 at 05:59
I sometimes get this error when I try running an uncompleted project deployment on Heroku. – akolliy May 22 '20 at 17:49
@david.barkhuizen I feel what you said is completely valid. But now how do i make the browser understand or send javascript file from the server – tencho Jul 09 '20 at 13:59

score 82 · Answer 2 · answered Aug 28 '10 at 20:19

82

Just an FYI for people who might have the same problem -- I just had to make my server send back the JSON as application/json and the default jQuery handler worked fine.

answered Aug 28 '10 at 20:19

Edward Abrams

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I think I am having the inverse of this problem. I'm requesting JSON from a third party API and they are returning application/javascript as the response and I am getting the same error you reported in this question. Not sure how to deal with it. – wuliwong May 09 '12 at 20:18
5

A strange problem is - it works fine on the localhost but not on the sever. Any idea why? – VishwaKumar Oct 15 '12 at 07:17
Hello. I have exact problem and I can't solve it, can someone tell me how you send JSON back to server – Alen Oct 25 '13 at 15:06
1

Thanks I was sending application/javascript (as I misread [this SO](http://stackoverflow.com/questions/477816/what-is-the-correct-json-content-type) ) and was getting this error on simple valid JSON. Changing it to `application/json` resolved the error. I'm not using JSONP. – scipilot Nov 07 '14 at 07:59
Even I'm getting the same error "Uncaught SyntaxError: Unexpected token :" , even after receiving the response in json format {"success":true,"data":2593} – Rupali Pemare Mar 16 '17 at 04:49

Grim... · Answer 3 · 2013-08-23T21:25:01.790

41

This has just happened to me, and the reason was none of the reasons above. I was using the jQuery command getJSON and adding callback=? to use JSONP (as I needed to go cross-domain), and returning the JSON code {"foo":"bar"} and getting the error.

This is because I should have included the callback data, something like jQuery17209314005577471107_1335958194322({"foo":"bar"})

Here is the PHP code I used to achieve this, which degrades if JSON (without a callback) is used:

$ret['foo'] = "bar";
finish();

function finish() {
    header("content-type:application/json");
    if ($_GET['callback']) {
        print $_GET['callback']."(";
    }
    print json_encode($GLOBALS['ret']);
    if ($_GET['callback']) {
        print ")";
    }
    exit; 
}

Hopefully that will help someone in the future.

edited Aug 23 '13 at 21:25

answered May 02 '12 at 11:35

Grim...

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It helped me a lot. We should wrap the json data with jsoncallback data whenever we are using jsonp method. Also the jsonpcallback data should not start with numbers. When I tried with numbers, it didn't worked out. When I tried it with the same format shown in this answer, it worked... – Ganesh Babu Sep 06 '13 at 08:46
True enough, but the error is the same and the code will degrade gracefully and still work if JSON is being used. – Grim... Dec 30 '15 at 16:26
This worked for me with AJAX, jQuery & JSONP. Thanks a lot! – Piotr Wittchen Mar 03 '17 at 18:33

score 18 · Accepted Answer · answered Jun 30 '10 at 20:27

18

I have just solved the problem. There was something causing problems with a standard Request call, so this is the code I used instead:

vote.each(function(element){                
  element.addEvent('submit', function(e){
    e.stop();
    new Request.JSON({
      url : e.target.action, 
      onRequest : function(){
        spinner.show();
      },
      onComplete : function(){
        spinner.hide();
      },
      onSuccess : function(resp){
        var j = resp;
        if (!j) return false;
        var restaurant = element.getParent('.restaurant');
        restaurant.getElements('.votes')[0].set('html', j.votes + " vote(s)");
        $$('#restaurants .restaurant').pop().set('html', "Total Votes: " + j.totalvotes);
        buildRestaurantGraphs();
      }
    }).send(this);
  });
});

If anyone knows why the standard Request object was giving me problems I would love to know.

answered Jun 30 '10 at 20:27

trobrock

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the difference between standard request and request.json is mostly in the headers, it adds `this.headers.extend({'Accept': 'application/json', 'X-Request': 'JSON'});` - go figure – Dimitar Christoff Jul 01 '10 at 09:53
Weird that that is what was causing the issue with this. – trobrock Jul 01 '10 at 14:50
3

What are the double `$$` there? – falsarella Sep 27 '12 at 12:51
@DimitarChristoff --any answer for falsarella about the $$? – bear Mar 06 '13 at 23:36
1

@bear The double dollar selector is defined in MooTools. – Anthony Faull Jul 09 '13 at 06:39
@melpomene, you're right. Comment removed to avoid confusion. – Keven Apr 24 '18 at 14:14

score 10 · Answer 5 · answered Dec 19 '13 at 02:50

I thought I'd add my issue and resolution to the list.

I was getting: Uncaught SyntaxError: Unexpected token < and the error was pointing to this line in my ajax success statement:

var total = $.parseJSON(response);

I later found that in addition to the json results, there was HTML being sent with the response because I had an error in my PHP. When you get an error in PHP you can set it to warn you with huge orange tables and those tables were what was throwing off the JSON.

I found that out by just doing a console.log(response) in order to see what was actually being sent. If it's an issue with the JSON data, just try to see if you can do a console.log or some other statement that will allow you to see what is sent and what is received.

I did this. I was echoing out json somewhere inmy php file and was getting php[//json data] in my response but I wasn't able to parse it. Thanks for posting this so I could figure out my own mistake. — Nicholas Decker, Jun 30 '14 at 20:37
OP problem is completely different. In your case you're trying to parse HTML as JSON, and in OP's case (s)he is trying to parse JSON as JavaScript. — Michał Perłakowski, Dec 29 '15 at 14:43

score 7 · Answer 6 · answered Dec 29 '15 at 14:38

When you request your JSON file, server returns JavaScript Content-Type header (text/javascript) instead of JSON (application/json).

According to MooTools docs:

Responses with javascript content-type will be evaluated automatically.

In result MooTools tries to evaluate your JSON as JavaScript, and when you try to evaluate such JSON:

{"votes":47,"totalvotes":90}

as JavaScript, parser treats { and } as a block scope instead of object notation. It is the same as evaluating following "code":

"votes":47,"totalvotes":90

As you can see, : is totally unexpected there.

The solution is to set correct Content-Type header for the JSON file. If you save it with .json extension, your server should do it by itself.

score 4 · Answer 7 · edited May 23 '17 at 12:02

It sounds like your response is being evaluated somehow. This gives the same error in Chrome:

var resp = '{"votes":47,"totalvotes":90}';
eval(resp);

This is due to the braces '{...}' being interpreted by javascript as a code block and not an object literal as one might expect.

I would look at the JSON.decode() function and see if there is an eval in there.

Similar issue here: Eval() = Unexpected token : error

Hammad Khan · Answer 8 · 2018-11-10T04:40:58.757

If nothing makes sense, this error can also be caused by PHP Error that is embedded inside html/javascript, such as the one below

<br />
<b>Deprecated</b>:  mysql_connect(): The mysql extension is deprecated and will be removed in the future: use mysqli or PDO instead in <b>C:\Projects\rwp\demo\en\super\ge.php</b> on line <b>54</b><br />
var zNodes =[{ id:1, pId:0, name:"ACE", url: "/ace1.php", target:"_self", open:true}

Not the <br /> etc in the code that are inserted into html by PHP is causing the error. To fix this kind of error (suppress warning), used this code in the start

error_reporting(E_ERROR | E_PARSE);

To view, right click on page, "view source" and then examine complete html to spot this error.

score 1 · Answer 9 · edited Oct 07 '18 at 14:12

1

I had the same problem and it turned out that the Json returned from the server wasn't valid Json-P. If you don't use the call as a crossdomain call use regular Json.

edited Oct 07 '18 at 14:12

Community

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answered Nov 13 '13 at 08:31

jakob

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OP uses JSON, not JSONP. – Michał Perłakowski Dec 29 '15 at 14:44

score 1 · Answer 10 · answered Mar 17 '15 at 10:11

"Uncaught SyntaxError: Unexpected token" error appearance when your data return wrong json format, in some case, you don't know you got wrong json format.
please check it with alert(); function

onSuccess : function(resp){  
   alert(resp);  
}

your message received should be: {"firstName":"John", "lastName":"Doe"}
and then you can use code below

onSuccess : function(resp){  
   var j = JSON.decode(resp); // but in my case i'm using: JSON.parse(resp); 
}

with out error "Uncaught SyntaxError: Unexpected token"
but if you get wrong json format
ex:

...{"firstName":"John", "lastName":"Doe"}

or

Undefined variable: errCapt in .... on line<b>65</b><br/>{"firstName":"John", "lastName":"Doe"}

so that you got wrong json format, please fix it before you JSON.decode or JSON.parse

I recommend using [`console.log()`](https://developer.mozilla.org/en-US/docs/Web/API/Console/log) instead of `alert()` for debugging. — Michał Perłakowski, Dec 29 '15 at 14:46

score 1 · Answer 11 · answered Mar 24 '16 at 22:31

This happened to me today as well. I was using EF and returning an Entity in response to an AJAX call. The virtual properties on my entity was causing a cyclical dependency error that was not being detected on the server. By adding the [ScriptIgnore] attribute on the virtual properties, the problem was fixed.

Instead of using the ScriptIgnore attribute, it would probably be better to just return a DTO.

score 1 · Answer 12 · answered Jan 26 '18 at 21:14

This happened to because I have a rule setup in my express server to route any 404 back to /# plus whatever the original request was. Allowing the angular router/js to handle the request. If there's no js route to handle that path, a request to /#/whatever is made to the server, which is just a request for /, the entire webpage.

So for example if I wanted to make a request for /correct/somejsfile.js but I miss typed it to /wrong/somejsfile.js the request is made to the server. That location/file does not exist, so the server responds with a 302 location: /#/wrong/somejsfile.js. The browser happily follows the redirect and the entire webpage is returned. The browser parses the page as js and you get

Uncaught SyntaxError: Unexpected token <

So to help find the offending path/request look for 302 requests.

Hope that helps someone.

score 1 · Answer 13 · answered Apr 11 '20 at 08:03

1

My mistake was forgetting single/double quotation around url in javascript:

so wrong code was:

window.location = https://google.com;

and correct code:

window.location = "https://google.com";

answered Apr 11 '20 at 08:03

Saeed Arianmanesh

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score 0 · Answer 14 · answered Jul 18 '13 at 19:52

0

I got a "SyntaxError: Unexpected token I" when I used jQuery.getJSON() to try to de-serialize a floating point value of Infinity, encoded as INF, which is illegal in JSON.

answered Jul 18 '13 at 19:52

Mark Cidade

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This question is about "Unexpected token **:**". – Michał Perłakowski Dec 29 '15 at 14:47

Shravan Ramamurthy · Answer 15 · 2015-09-26T04:10:14.900

0

In my case i ran into the same error, while running spring mvc application due to wrong mapping in my mvc controller

@RequestMapping(name="/private/updatestatus")

i changed the above mapping to

 @RequestMapping("/private/updatestatus")

or

 @RequestMapping(value="/private/updatestatus",method = RequestMethod.GET)

edited Sep 26 '15 at 04:10

answered Sep 26 '15 at 03:58

Shravan Ramamurthy

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score 0 · Answer 16 · answered Jun 21 '17 at 13:47

For me the light bulb went on when I viewed the source to the page inside the Chrome browser. I had an extra bracket in an if statement. You'll immediately see the red circle with a cross in it on the failing line. It's a rather unhelpful error message, because the the Uncaught Syntax Error: Unexpected token makes no reference to a line number when it first appears in the console of Chrome.

score 0 · Answer 17 · answered Jul 21 '17 at 06:13

0

I did Wrong in this

   `var  fs = require('fs');
    var fs.writeFileSync(file, configJSON);`

Already I intialized the fs variable.But again i put var in the second line.This one also gives that kind of error...

answered Jul 21 '17 at 06:13

Janen R

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score 0 · Answer 18 · answered Feb 02 '18 at 05:08

0

For those experiencing this in AngularJs 1.4.6 or similar, my problem was with angular not finding my template because the file at the templateUrl (path) I provided couldn't be found. I just had to provide a reachable path and the problem went away.

answered Feb 02 '18 at 05:08

lwdthe1

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i solved the same issue by correcting the baseref url - pointed to root folder => – Abdeali Chandanwala Oct 15 '18 at 11:14

score 0 · Answer 19 · answered Dec 20 '18 at 18:01

0

In my case it was a mistaken url (not existing), so maybe your 'send' in second line should be other...

answered Dec 20 '18 at 18:01

Michal - wereda-net

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score 0 · Answer 20 · answered Oct 06 '20 at 10:15

0

This error might also mean a missing colon or : in your code.

answered Oct 06 '20 at 10:15

Cons Bulaquena

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score -2 · Answer 21 · answered Sep 24 '13 at 09:21

-2

Uncaught SyntaxError: Unexpected token }

Chrome gaved me the error for this sample code:

<div class="file-square" onclick="window.location = " ?dir=zzz">
    <div class="square-icon"></div>
    <div class="square-text">zzz</div>
</div>

and solved it fixing the onclick to be like

... onclick="window.location = '?dir=zzz'" ...

But the error has nothing to do with the problem..

answered Sep 24 '13 at 09:21

ungalcrys

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OP asked about "Unexpected token **:**". – Michał Perłakowski Dec 29 '15 at 14:48

Uncaught SyntaxError: Unexpected token :

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