title: JavaScript doesn't work in my browser but works in CodePen
body: <p>It's very strange and, as I do not have much experience yet, I don't understand the problem of my JavaScript not working. I made a ToTop button. </p>
  
  <p>In CodePen it works fine. As I scroll down it fades in &amp; out. CodePen: <a href="http://bit.ly/1ttnjRi" rel="nofollow">http://bit.ly/1ttnjRi</a></p>
  
  <p>But in Chrome it does nothing. Also, I sent all files to a friend and he had the same problem. </p>
  
  <p>Can someone help me? Thanks!</p>
  
  <p>UPDATE: </p>
  
  <p>Debug console gives this: Uncaught ReferenceError: $ is not defined </p>
  
  <p>P.S. What is the purpose of down voting? Possibly I am not the only one newbie encountering this problem. I guess stackoverflow is for helping each other in the uneasy coding stuff, not bragging about knowing something more and because of that being arrogant. Have a nice day! :)</p>