esri.request({ url:"http://..../rest/services/USA/MapServer", content: { param1: "value1", param2: "value2", param3: "value3" }, callbackParamName:"callback", load:function(response, io) { ... }, error:esriConfig.defaults.io.errorHandler });
This has already been baked into the JavaScript API. You can use an esri namespace method called "esri.request(...)"
The full API reference documentation for the method is at : http://http://help.arcgis.com/en/webapi/javascript/arcgis/help/jsapi/namespace_esri.htm#requestesri.request({ url:"http://..../rest/services/USA/MapServer", content: { param1: "value1", param2: "value2", param3: "value3" }, callbackParamName:"callback", load:function(response, io) { ... }, error:esriConfig.defaults.io.errorHandler });