One thing to remember is.
getJson is just a thin wrapper for:
getJSON: function( url, data, callback ) {
return jQuery.get(url, data, callback, "json");
},
Which in turn is a thin wrapper for get:
get: function( url, data, callback, type ) {
// shift arguments if data argument was omited
if ( jQuery.isFunction( data ) ) {
type = type || callback;
callback = data;
data = null;
}
return jQuery.ajax({
type: "GET",
url: url,
data: data,
success: callback,
dataType: type
});
},
Which simply boils down to a call to $.ajax, which has a simple failure and success handler.
So you could simply do:
$.ajax({
type: "GET",
url: url,
data: data,
success: callback,
dataType: "json",
error: failureCallback
});