send image data across domains

send-image.js

var canvas = document.getElementById("canvas"),
    image  = canvas.toDataURL("image/png");

$.ajax({
  url: "https://app-engine-identifier.appspot.com/upload",
  type: "POST",            
  data: { imgdata : image },
  crossDomain: true,
  success: function(data){ 
    console.log(data);   // yayyy
  },
  error: function(error){
    throw error;  // ;_;
  }
});