Javascript/Theory.html at main · CodeFletcher/Javascript · GitHub

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<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>video 2</title>
  </head>
  <body>
    <p>Everything in javascript happens in Execution Context.</p>
    <p>
      Javascript is a synchronous single threaded language that means it can
      execute one line of code at a time.
    </p>
    <hr />

    <p>
      Function along with its lexical scope bundle together to form closures.
    </p>

    <hr />

    <ol>
      <li>
        Function that is passed on as argument to another function is called
        callback function.
      </li>
      <li>Event listeners can also invoke closures with scope.</li>
      <li>
        Event listeners consume a lot of memory which can potentially slow down
        the website therefore it is good practice to remove if it is not used.
      </li>
    </ol>
    <button id="my-btn">Click Me</button>

    <hr />

    <p>Event loop for javascript</p>
    <ul>
      <li>
        call stack is maintained by js engine while callback queue & microtask
        queue is maintained by browser(web apis).
      </li>
      <li>microtask queue has priority over callback queue.</li>
      <li>
        callback queue & microtask queue are pushed by event loop only when call
        stack is empty.
      </li>
    </ul>
    <!-- <script src="Video-2.js"></script>
    <script src="Functions.js"></script>
    <script src="Closures.js"></script> -->
    <script src="CallbackFunctions.js"></script>
  </body>
</html>