Should be really simple Jquery jsonp

Why does this not work? anybody:

In my code I have:

$.getJSON("http://isp123.co.uk/cw/NorthWales/Test.txt?jsoncallback=?",
        function(data){
                //This never gets executed
            alert('here');
          });

The text file can be viewed her开发者_如何学运维e:

http://isp123.co.uk/cw/NorthWales/Test.txt

This is not a JSONP response:

({"name" : "hello world"});

If you had a proper JSONP response, then your code should work.

The question mark in the "callback=?" part of the URL is changed by jQuery before making the request, your JSONP server needs to be able to dynamically create the JSONP "function" in response to the unique jQuery request. If you can't dynamically create your JSONP, perhaps you could use YQL/Yahoo pipes to turn it into JSONP?

This pipe should do the trick, to see if it works, use this URL instead in your getJSON function: http://pipes.yahoo.com/pipes/pipe.run?u=http%3A%2F%2Fisp123.co.uk%2Fcw%2FNorthWales%2FTest.txt&_id=332d9216d8910ba39e6c2577fd321a6a&_render=json&_callback=?

I just tried this and it worked:

$.getJSON("http://pipes.yahoo.com/pipes/pipe.run?u=http%3A%2F%2Fisp123.co.uk%2Fcw%2FNorthWales%2FTest.txt&_id=332d9216d8910ba39e6c2577fd321a6a&_render=json&_callback=?", function(data){
    //This always gets executed!!!
    alert('here');
});

I don't know if you know enough about JSONP but this is not JSONP

?({"name" : "hello world"});

It really should be something like this http://isp123.co.uk/cw/NorthWales/Test.txt?jsoncallback=foo

foo({"name" : "hello world"});

From the jQuery.getJson manual page:

Important: As of jQuery 1.4, if the JSON file contains a syntax error, the request will usually fail silently. Avoid frequent hand-editing of JSON data for this reason. JSON is a data-interchange format with syntax rules that are stricter than those of JavaScript's object literal notation. For example, all strings represented in JSON, whether they are properties or values, must be enclosed in double-quotes. For details on the JSON format, see http://json.org/.

Your JSON is invalid according to http://jsonlint.com/

Here Clearly mentioned

As of jQuery 1.5, setting the jsonp option to false prevents jQuery from adding the "?callback" string to the URL or attempting to use "=?" for transformation. In this case, you should also explicitly set the jsonpCallback setting

and read jsonpCallback section

jsonpCallback,

Specify the callback function name for a JSONP request. This value will be used instead of the random name automatically generated by jQuery. It is preferable to let jQuery generate a unique name as it'll make it easier to manage the requests and provide callbacks and error handling. You may want to specify the callback when you want to enable better browser caching of GET requests. As of jQuery 1.5, you can also use a function for this setting, in which case the value of jsonpCallback is set to the return value of that function

Probably worth using jQuery.ajax() - http://api.jquery.com/jQuery.ajax/

You can pass in the dataType as "jsonp" and then jQuery takes care of all the callback business, but more importantly you can specify a function to run when there's an error, which may help you:

$.ajax({
    dataType: "jsonp",
    success: function(d) {console.log(d);},
    error: function() { console.log("error") } //do your debugging in here
    //add other parameters such as URL, etc
});

The error function you define can be passed 3 variables, read up on it on the ajax() page on the jQuery docs (linked at the beginning of my post) to find out more about that and how to use them.

Your problem lies with how your server is outputting the information. In the link you've supplied, the assumption is that any name placed in the ?jsonpcallback should result in wrapping the JSONP code in a function with that same name. It, however, is not the case.

So the next option is this: use a static function name in your server file and wrap the code. (e.g. use foo(<jsonp>) and stick with it) Then, you have to explicitly tell jQuery that we are going to use a specific function name (leave jQuery with the assumption it's supplying (and thus receiving) that name back, when in-fact you're just supplying it server side and filling in the blanks).

Once you have your file setup, use something like the following:

$.ajax({
  // setup the request
  url: 'http://isp123.co.uk/cw/NorthWales/Test.txt',
  crossDomain: true,
  dataType: 'jsonp',
  jsonp: false,
  jsonpCallback: 'foo', // "supply" the jsonp function (pseudo-defined)

  // function to call when completed
  complete: function(data){
    alert(data);
  }

  // just in case, catch the error
  error: function(j,t,e){
    alert('AJAX Error');
  }
});

So now when jQuery makes the call and it thinks it's supplying the callback, it's really just getting the server-defined callback in return. So, for the above to work, your text file should look something like this:

foo({name:"Hello, World!"});

Also, if you can, change your header to application/javascript, though this is some-what optional.