gistfile1.js

// dojo
dojo.io.bind({
    url: "/dragons",
    load: function(type, data, evt){ /*do something w/ the data */ }
    mimetype: "text/json"
});

// jQuery
jQuery.get("/dragons", function(data, textStatus){
  /*do something w/ the data */ 
}, "json");

// Prototype
new Ajax.Request('/dragons', {
  onSuccess: function(response) {
    /*do something w/ the data */
  }
});