Javascript for shopping cart.txt

updateCartTotal();

document.getElementById("emptycart").addEventListener("click", emptyCart);
var btns = document.getElementsByClassName('addtocart');
for (var i = 0; i < btns.length; i++) {
  btns[i].addEventListener('click', function() {addToCart(this);});
}


function addToCart(elem) {
  var sibs = [];
  var getprice;
  var getproductName;
  var cart = [];
   var stringCart;
  while(elem = elem.previousSibling) {
      if (elem.nodeType === 3) continue;
      if(elem.className == "price"){
          getprice = elem.innerText;
      }
      if (elem.className == "productname") {
          getproductName = elem.innerText;
      }
      sibs.push(elem);
  }
  //create product object
  var product = {
      productname : getproductName,
      price : getprice
  };
  //convert product data to JSON for storage
  var stringProduct = JSON.stringify(product);
  /*send product data to session storage */

  if(!sessionStorage.getItem('cart')){
      //append product JSON object to cart array
      cart.push(stringProduct);
      //cart to JSON
      stringCart = JSON.stringify(cart);
      //create session storage cart item
      sessionStorage.setItem('cart', stringCart);
      addedToCart(getproductName);
      updateCartTotal();
  }
  else {
      //get existing cart data from storage and convert back into array
     cart = JSON.parse(sessionStorage.getItem('cart'));
      //append new product JSON object
      cart.push(stringProduct);
      //cart back to JSON
      stringCart = JSON.stringify(cart);
      //overwrite cart data in sessionstorage
      sessionStorage.setItem('cart', stringCart);
      addedToCart(getproductName);
      updateCartTotal();
  }
}
/* Calculate Cart Total */
function updateCartTotal(){
  //init
  var total = 0;
  var price = 0;
  var items = 0;
  var productname = "";
  var carttable = "";
  if(sessionStorage.getItem('cart')) {
      //get cart data & parse to array
      var cart = JSON.parse(sessionStorage.getItem('cart'));
      //get no of items in cart
      items = cart.length;
      //loop over cart array
      for (var i = 0; i < items; i++){
          //convert each JSON product in array back into object
          var x = JSON.parse(cart[i]);
          //get property value of price
          price = parseFloat(x.price.split('$')[1]);
          productname = x.productname;
          //add price to total
          carttable += "<tr><td>" + productname + "</td><td>$" + price.toFixed(2) + "</td></tr>";
          total += price;
      }

  }
  //update total on website HTML
  document.getElementById("total").innerHTML = total.toFixed(2);
  //insert saved products to cart table
  document.getElementById("carttable").innerHTML = carttable;
  //update items in cart on website HTML
  document.getElementById("itemsquantity").innerHTML = items;
}
//user feedback on successful add
function addedToCart(pname) {
var message = pname + " was added to the cart";
var alerts = document.getElementById("alerts");
alerts.innerHTML = message;
if(!alerts.classList.contains("message")){
   alerts.classList.add("message");
}
}
/* User Manually empty cart */
function emptyCart() {
  //remove cart session storage object & refresh cart totals
  if(sessionStorage.getItem('cart')){
      sessionStorage.removeItem('cart');
      updateCartTotal();
    //clear message and remove class style
    var alerts = document.getElementById("alerts");
    alerts.innerHTML = "";
    if(alerts.classList.contains("message")){
        alerts.classList.remove("message");
    }
  }
}