When developing a Chrome Extension, how to determine if it is running for the first time?

Here is my json and js file that am using:

manifest.json:
{
"name": "MyExtension",
"version": "1.0",
"description": "Bravo watch videos here!",
"permissions": ["tabs", "http://*/*"],
"content_scripts" : [{
"matches" : [ "www.youtube.com/*"],
"js" : ["shafali.js"]
}]
}

shafali.js :

function state() { console.log("State transit"); }
var player = document.getElementById("videoPlayer");
player.addEventListener("onStateChange", "state");
console.log("Started!");

I am trying to use the above code when developing my chrome extension which is to play youtube videos. But when I see the console the msg shows only 'Started!' not 'State transit' . What am I doing wrong?