In the world of Javascript, scope is basically a fancy word for availability. Is this varaible something I can access from where I am now?. There are two main scopes 'global scope' and 'local scope'. Global scope means that the variable you declare are available everywhere in your application. Local scope means variables are self-contained to just the function you decleared the variable in.
Global scope Ex) var counter = 0; (varaiable is declared), function returnCount() { return counter; } (Because counter has been declared earlier on globally this function can access variable).
Local scope Ex) function setState() {var state = "on"; alert(state)//on} (In here variable state has been declared locally so alert underneath this var state could be defined). setState(); alert (state) // undefined (becuase variable State has not been defined on the second one alert state would be undefined).
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