JsLog.me tracking code hooks on
console calls. It send logged information to the cloud, where you can analyze it later.
Sending to the server performed in the "soft" way and do not really affect application performance even if logging big messages, or large amount of messages. It concatenates consecutive messages in large packets and send them asynchronously.
It also works good in offline mode for mobile Phonegap/Cordova apps. When server is not available due to network or server issues, it is stored locally in a browser's local storage. To not affect running application, used space for pending messages is limited to 1Mb.