diff --git a/debugging/book-library/script.js b/debugging/book-library/script.js
index 75ce6c1d..35920d8b 100644
--- a/debugging/book-library/script.js
+++ b/debugging/book-library/script.js
@@ -1,6 +1,6 @@
 let myLibrary = [];
 
-window.addEventListener("load", function (e) {
+window.addEventListener("load", function () {
   populateStorage();
   render();
 });
@@ -28,60 +28,72 @@ const check = document.getElementById("check");
 //check the right input from forms and if its ok -> add the new book (object in array)
 //via Book function and start render function
 function submit() {
-  if (
-    title.value == null ||
-    title.value == "" ||
-    pages.value == null ||
-    pages.value == ""
-  ) {
-    alert("Please fill all fields!");
+  // 1. Preprocess and store cleaned values in variables / removes spaces from the beginning and end
+  const cleanTitle = title.value.trim();
+  const cleanAuthor = author.value.trim();
+
+  // Convert string input to a Number for calculation/validation
+  const pageCount = Number(pages.value);
+  const isRead = check.checked;
+
+  // 2. VALIDATION: // Check if strings are empty after trimming spaces
+  if (cleanTitle === "" || cleanAuthor === "") {
+    alert("Title and Author cannot be empty!");
+    return false;
+  }
+  // Check if page count is a valid number and greater than 0
+  if (isNaN(pageCount) || pageCount <= 0) {
+    alert("Please enter a valid number of pages!");
     return false;
-  } else {
-    let book = new Book(title.value, title.value, pages.value, check.checked);
-    library.push(book);
-    render();
   }
+
+  // 3. If all validations pass, create a new Book object and add it to the library
+  let book = new Book(cleanTitle, cleanAuthor, pageCount, isRead);
+  myLibrary.push(book);
+
+  // 4. Clear the form fields after submission
+  title.value = "";
+  author.value = "";
+  pages.value = "";
+  check.checked = false;
+
+  render();
 }
 
-function Book(title, author, pages, check) {
-  this.title = title;
-  this.author = author;
-  this.pages = pages;
-  this.check = check;
+class Book {
+  constructor(title, author, pages, check) {
+    this.title = title;
+    this.author = author;
+    this.pages = pages;
+    this.check = check;
+  }
 }
 
 function render() {
-  let table = document.getElementById("display");
-  let rowsNumber = table.rows.length;
+  const table = document.getElementById("display");
+  const tbody = table.querySelector("tbody");
   //delete old table
-  for (let n = rowsNumber - 1; n > 0; n-- {
-    table.deleteRow(n);
+  if (tbody) {
+    tbody.innerHTML = "";
   }
   //insert updated row and cells
-  let length = myLibrary.length;
+  const length = myLibrary.length;
   for (let i = 0; i < length; i++) {
-    let row = table.insertRow(1);
-    let titleCell = row.insertCell(0);
-    let authorCell = row.insertCell(1);
-    let pagesCell = row.insertCell(2);
-    let wasReadCell = row.insertCell(3);
-    let deleteCell = row.insertCell(4);
-    titleCell.innerHTML = myLibrary[i].title;
-    authorCell.innerHTML = myLibrary[i].author;
-    pagesCell.innerHTML = myLibrary[i].pages;
+    const row = table.insertRow(-1);
+    const titleCell = row.insertCell(0);
+    const authorCell = row.insertCell(1);
+    const pagesCell = row.insertCell(2);
+    const wasReadCell = row.insertCell(3);
+    const deleteCell = row.insertCell(4);
+    titleCell.textContent = myLibrary[i].title;
+    authorCell.textContent = myLibrary[i].author;
+    pagesCell.textContent = myLibrary[i].pages;
 
     //add and wait for action for read/unread button
-    let changeBut = document.createElement("button");
-    changeBut.id = i;
+    const changeBut = document.createElement("button");
     changeBut.className = "btn btn-success";
     wasReadCell.appendChild(changeBut);
-    let readStatus = "";
-    if (myLibrary[i].check == false) {
-      readStatus = "Yes";
-    } else {
-      readStatus = "No";
-    }
-    changeBut.innerText = readStatus;
+    changeBut.innerText = myLibrary[i].check ? "Yes" : "No";
 
     changeBut.addEventListener("click", function () {
       myLibrary[i].check = !myLibrary[i].check;
@@ -89,15 +101,15 @@ function render() {
     });
 
     //add delete button to every row and render again
-    let delButton = document.createElement("button");
-    delBut.id = i + 5;
-    deleteCell.appendChild(delBut);
-    delBut.className = "btn btn-warning";
-    delBut.innerHTML = "Delete";
-    delBut.addEventListener("clicks", function () {
-      alert(`You've deleted title: ${myLibrary[i].title}`);
+    const delButton = document.createElement("button");
+    deleteCell.appendChild(delButton);
+    delButton.className = "btn btn-warning";
+    delButton.innerHTML = "Delete";
+    delButton.addEventListener("click", function () {
+      const deletedTitle = myLibrary[i].title;
       myLibrary.splice(i, 1);
       render();
+      alert(`You've deleted title: ${deletedTitle}`);
     });
   }
 }