将jsonp与Ajax HTML结合使用

I have a simple html page that I open directly, file://abc.html

It has the following code

  $.ajax({
        url: "http://localhost:8080/ajax_info.php",
        dataType: "jsonp",
        jsonp: 'jsoncallback',
        success: function(data) {
            alert(data);
        }
    });

ajax_info.php has echo 'hello' only in it.

On each reload the Network tab in chrome shows that a request is made to

http://localhost:8080/ajax_info.php?jsoncallback=jQuery1111016803214247142373_1471278920224&_=1471278920236

and hello as a response is received but I dont get the alert box.

When I execute the page it shows nothing (no alert box), I am supposed to get alert with hello in it, Am I doing something wrong ?

Try adding this function to yours:

function jsoncallback(json){
 alert(json);
}

EDIT: and when you want to use JSONP the server should echo params in the function you want:

do this on server

echo 'jsoncallback("hello!")';

or this:

echo 'jsoncallback('. json_encode($some_data) .')';

Of course 'jsoncallback' is the name of user function, that any user may want to change, so you have to do it right way:

echo $user_sent_me_this_name . '(' . json_encode($some_data) . ')';

 success: function(data) {alert(data);}

This code is fine , make sure that your Ajax connection is working. to know that you can use error: parameter.

$.ajax({
        url: "http://localhost:8080/ajax_info.php",
        dataType: "jsonp",
        jsonp: 'jsoncallback',
        success: function(data) {
            alert(data);
        },
        error: function() {
             $('#info').html('<p>An error has occurred</p>');
          }
    });