I am trying to send a POST request to Drupal's Services module & JSON_Server module, however I am getting

{ "#error": true, "#data": "Invalid method " }

Since PhoneGap runs html files from locally on the phone, should i need to worry about JSONP. The issue I have with that is that I must POST data, and JSONP only allows for GET. Any ideas would be helpful. Thanks!

//SEND REQUEST AND CALLBACK FUNCTION
var req;
DrupalService.prototype.request = function(dataObject, callback){

    req = false;

    var url = DRUPAL_JSON_URL;
    var params = "data="+dataObject;

    try {
    	req = new XMLHttpRequest();
    } catch(e) {
    	req = false;
    }

    if(req) {
    	req.onreadystatechange = function() {//Call a function when the state changes.
    		if(req.readyState == 4 && req.status == 200) {
    			console.log(">> "+req.responseText);
    		}
    	}

req.open("POST", url, false);
    	req.send(params);
    }

}