title: What does "tx" mean in callback function when calling Phonegap/Cordova `transaction` method?
body: <p>From the official doc of Cordova/Phonegap <a href="http://docs.phonegap.com/en/edge/cordova_storage_storage.md.html#openDatabase" rel="nofollow noreferrer">on transaction method</a>, the parameter reads <code>tx</code>.</p>
  
  <p>What does <code>tx</code> mean?</p>
  
  <p><img src="https://i.stack.imgur.com/E8KD7.png" alt="enter image description here"></p>