syntax error: unexpected token <

This usually happens when you're including or posting to a file which doesn't exist. The server will return a regular html-formatted "404 Not Found" enclosed with

'<html></html>'

tags. That first chevron < isn't valid js nor valid json, therefore it triggers an unexpected token.

What if you try to change 'funcoes/enquete_adm.php' to an absolute url, just to be sure?

EDIT (several years later)

The root cause might not always come from 404 errors. Sometimes you can make a request to an API and receive HTML formatted errors. I've stumbled to a couple of cases in which the API endpoint should have returned

{
   error: "you must be authenticated to make this request"
}

With header 401. And instead I got

<html>You must be authenticated to make this request</html>

With header 200.

Given the header is 200 you can't tell the request has failed beforehand, and you're stuck to try and JSON.parse the response to check if it's valid.

You have unnecessary ; (semicolons):

Example here:

 }else{
        $('#resposta').addClass('warning-box').html('É necessário no mínimo duas opções');
    };

The trailing ; after } is incorrect.

Another example here:

}else{
    $('#resposta').addClass('warning-box').html('Coloque a pergunta da enquete');
};

I suspect you're getting text/html encoding in response to your request so I believe the issue is:

dataType : 'json',

try changing it to

dataType : 'html',

From http://api.jquery.com/jQuery.get/:

dataType Type: String The type of data expected from the server. Default: Intelligent Guess (xml, json, script, or html).

The error SyntaxError: Unexpected token < likely means the API endpoint didn't return JSON in its document body, such as due to a 404.

In this case, it expects to find a { (start of JSON); instead it finds a < (start of a heading element).

Successful response:

<html>
  <head></head>
  <body>
    {"foo": "bar", "baz": "qux"}
  </body>
</html>

Not-found response:

<html>
  <head></head>
  <body>
    <h1>Not Found</h1>
    <p>The requested URL was not found on the server.  If you entered the URL manually please check your spelling and try again.</p>
  </body>
</html>

Try visiting the data endpoint's URL in your browser to see what's returned.

I had a similar problem, and my issue was that I was sending javascript to display console messages.

Even when I looked at the file in my browser (not through the application) it showed exactly as I expected it to (eg the extra tags weren't showing), but there were showing in the html/text output and were trying to be parsed.

Hope this helps someone!

syntax error: unexpected token <

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