rem: alert(err); 
add: dump(err); 
context:     getLitmusJson : function(ID, callback, prefix) {        var url = litmus.baseURL+'json.cgi?' + prefix + ID;        var d = loadJSONDoc(url);		d.addBoth(function (res) { 			d.deferred = null;  			return res; 		});		d.addCallback(callback);		d.addErrback(function (err) {             if (err instanceof CancelledError) {                 return;             }            alert(err);        });    },
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/9421/838a3f38df6e9bd6fd899d9909b263e01aed1e26/litmus.js/clean/testing/extensions/community/chrome/content/litmus.js