domProject.html

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>DOM Projects</title>
  <style>
     body{
      font-family:arial;
    }
    button.subsBtn{
        padding: 10px;
        padding-left: 15px;
        padding-right: 15px;
        background-color: black;
        color: white;
        border-radius: 28px;
        font-weight: bold;
        cursor: pointer;
        margin-bottom: 30px;
    }
    button.subscribedNew{
      background-color: white;
      color: black;
      border-color: white;;
    }
    input.calInp {
      padding: 10px;
    }
    h4.am{
      font-size: 15px;
    }
    button.calbtn{
      background-color: green;
      color: white;
      padding: 10px;
    }
  </style>
</head>
<body>
  <H4>YouTube Subscribe Button</H4>
  <button class="subsBtn" onclick="subscribeFun()">Subscribe</button>
  <p>Rock Paper Scisoors <a href="rock_paper_function_object.html">Click here</a></p> 

  <h4 class="am">Amazon Shipping Calculator</h4>
  <p>Orders Under $40 = $10 Shipping.<br>Order Over $40 = Free Shipping.</p>

  <input placeholder="Enter Amount" class="calInp" onkeydown="handCosy(event)">
  <button onclick="shippingCal()" class="calbtn">Calculate</button>
  <p class="displayCost"></p>


  <script>
    function subscribeFun(){
      const btnElement = document.querySelector('.subsBtn');
      if(btnElement.innerHTML === 'Subscribe'){
        btnElement.innerHTML = 'Subscribed';
        btnElement.classList.add('subscribedNew');

      }else{
        btnElement.innerHTML = 'Subscribe';
        btnElement.classList.remove('subscribedNew');
      }
    }

    //function for shipping cal
    function shippingCal(){
      const inputEle = document.querySelector('.calInp');
      let inpValue = Number(inputEle.value);
      if(inpValue < 40){
        inpValue = (inpValue*100) + 1000; //convert into cents
      }else{
        inpValue = inpValue;
      }
      document.querySelector('.displayCost')
        .innerHTML = `$${(inpValue)/100}`; //convert back into $$
    }

    function handCosy(event){
      if(event.key === 'Enter'){
      shippingCal();
      }
    }
  </script>
</body>
</html>