-     arrays
  -     document.getElementById()
  -     document.querySelector()
  -     addEventListener()
  -     document.body.style.backgroundColor
  -     Math.floor()
  -     Math.random()
  -     array.length
  -     CSS custom properties

      - document.querySelectorAll()
      - forEach()
      - addEventListener()
      - currentTarget property
      - classList
      - textContent

  -	objects
  -	DOMContentLoaded
  -	addEventListener()
  -	array.length
  -	textContent
  -	img.src
  -     Math.floor()
  -     Math.random()

  -	document.querySelector()
  -	addEventListener()
  -	classList.contains()
  -	classList.remove()
  -	classList.add()
  -	classList.toggle()
  -	Template literals ${}
  -     CSS: height: auto vs height: 100%

  -	document.querySelector()
  -	addEventListener()
  -	classList.toggle()
  -	classList.remove()

  -	document.querySelector()
  -	addEventListener()
  -	classList.add()
  -	classList.remove()
  -	MISTAKE LEARNED

  -	document.querySelectorAll()
  -	addEventListener()
  -	forEach() to addEventListener()
  -	event.currentTarget.parentElement()
  -	classList.remove()
  -	classList.toggle()
  -	traversing the DOM vs targeting selectors inside element
  -     Nodelist concept
  -     CSS: multiple class selectors vs double class selector

  -	arrays
  -	objects
  -	forEach()
  -	DOMContentLoaded
  -	map(), reduce(), and filter()
  -	innerHTML
  -	includes method
  -     currentTarget.dataset()
  -     2 ways of using .join()
  -     

  -	document.querySelector()
  -	addEventListener()
  -	classList.contains()
  -	classList.add()
  -	classList.remove()
  -	play()
  -	pause()
  -     window.addEventListener('load' vs 'DOMContentLoaded')

  -	document.getElementById()
  -	new Date().getFullYear()
  -	getBoundingClientRect()
  -	slice() method
  -	window.scrollTo()
  -     HTMLElement.style
  -     window.pageYOffset
  -     document.querySelectorAll()
  -     event.preventDefault()
  -     element.getAttribute()
  -     HTMLElement.offsetTop
  -     window.addEventListener('scroll')

  -	classList.add()
  -	classList.remove()
  -	forEach()
  -	addEventListener()
  -     event.target()
  -     IF or BOOLEAN

  -	getFullYear()
  -	getMonth()
  -	getDate()
  -	Math.floor()
  -	setInterval()
  -	clearInterval()

  -	parseInt()
  -	Math.floor()
  -	Math.random()
  -	isNaN()
  -	slice method
  -	event.preventDefault()
  -     .addEventListener('submit')

-	      DOMContentLoaded
- 	new Date()
-       .createElement()
- 	.createAttribute()
-	      .setAttributeNode()
- 	.appendChild()
-	      filter()
- 	map()
-       settimeout()
-       .removeChild()
-       .previousElementSibling
-       element.querySelector vs document.querySelector
-       .localStorage

-	      querySelectorAll()
- 	addEventListener()
- 	forEach()
-	      if/else statements

  -  IF or Conditional (ternary) operator