cross-domain jquery 1.6.2 ajax call is trying to call from same domain

I have an api set up on another domain, domain B (api.domainb.com), and want to make a call to it from domain A (www.domaina.com). However, when I do a call from domain A to domain B via jquery ajax, jquery ends up trying to call www.dom开发者_StackOverflow社区aina.com/api.domainb.com which obviously will return an error. Here is the relevant javascript code

    $.ajax(
      url: 'http://api.domainb.com',
      type: 'GET',
      dataType: 'jsonp',
      data: {hello: 'world'}, 
      crossDomain: true,
      success: function(data){
        alert(JSON.stringify(data))
      }, 
      error: function(error){
        alert(JSON.stringify(error))
      });

Eventually, the code in domain A and domain B will be on the same domain, but for now, I need to make a cross-domain call. Any suggestions as to how to make this work?

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You're just missing the protocol so that the Ajax call knows it's a different domain and not a relative URL. Try using url: 'http://api.domainb.com'.

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You cannot make cross-domain calls; browsers simply do not allow it in general. However, the reason you're seeing the behavior you describe is that your URL is missing the "http://" prefix.

There are some things you can do with fairly new HTML5 APIs to sort-of "get permission" to do cross-domain calls.

edit @Dan points out correctly that while XMLHttpRequest (what people usually call "ajax") won't do cross-domain stuff (CORS aside), it's possible to leverage the fact that <script> tags can reference other domains in order to put together a service. The server-side code has to be different, however. (That's usually called "JSONP".)