diff --git a/debugging/book-library/index.html b/debugging/book-library/index.html
index 23acfa71..b3932522 100644
--- a/debugging/book-library/index.html
+++ b/debugging/book-library/index.html
@@ -1,12 +1,9 @@
 <!DOCTYPE html>
-<html>
+<html lang="en">
   <head>
-    <title> </title>
-    <meta
-      charset="utf-8"
-      name="viewport"
-      content="width=device-width, initial-scale=1.0"
-    />
+    <title>Library</title>
+    <meta charset="utf-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
     <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.min.js"></script>
     <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.min.js"></script>
@@ -31,7 +28,7 @@ <h1>Library</h1>
       <div class="form-group">
         <label for="title">Title:</label>
         <input
-          type="title"
+          type="text"
           class="form-control"
           id="title"
           name="title"
@@ -39,7 +36,7 @@ <h1>Library</h1>
         />
         <label for="author">Author: </label>
         <input
-          type="author"
+          type="text"
           class="form-control"
           id="author"
           name="author"
@@ -51,6 +48,8 @@ <h1>Library</h1>
           class="form-control"
           id="pages"
           name="pages"
+          min="1"
+          step="1"
           required
         />
         <label class="form-check-label">
diff --git a/debugging/book-library/script.js b/debugging/book-library/script.js
index 75ce6c1d..9b07d066 100644
--- a/debugging/book-library/script.js
+++ b/debugging/book-library/script.js
@@ -1,4 +1,4 @@
-let myLibrary = [];
+const myLibrary = [];
 
 window.addEventListener("load", function (e) {
   populateStorage();
@@ -7,8 +7,8 @@ window.addEventListener("load", function (e) {
 
 function populateStorage() {
   if (myLibrary.length == 0) {
-    let book1 = new Book("Robison Crusoe", "Daniel Defoe", "252", true);
-    let book2 = new Book(
+    const book1 = new Book("Robison Crusoe", "Daniel Defoe", "252", true);
+    const book2 = new Book(
       "The Old Man and the Sea",
       "Ernest Hemingway",
       "127",
@@ -16,29 +16,38 @@ function populateStorage() {
     );
     myLibrary.push(book1);
     myLibrary.push(book2);
-    render();
   }
 }
 
-const title = document.getElementById("title");
-const author = document.getElementById("author");
-const pages = document.getElementById("pages");
-const check = document.getElementById("check");
+const titleInput = document.getElementById("title");
+const authorInput = document.getElementById("author");
+const pagesInput = document.getElementById("pages");
+const checkInput = 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!");
-    return false;
-  } else {
-    let book = new Book(title.value, title.value, pages.value, check.checked);
-    library.push(book);
+  titleInput.value == "" ||
+  authorInput.value == "" ||
+  pagesInput.value == ""
+) {
+  alert("Please fill all fields!");
+  return false;
+}
+
+if (Number(pagesInput.value) < 1 || !Number.isInteger(Number(pagesInput.value))) {
+  alert("Pages must be a whole number of 1 or more");
+  return false;
+}
+ else {
+    let book = new Book(
+      titleInput.value.trim(),
+      authorInput.value.trim(),
+      Number(pagesInput.value),
+      checkInput.checked
+    );
+    myLibrary.push(book);
     render();
   }
 }
@@ -46,58 +55,56 @@ function submit() {
 function Book(title, author, pages, check) {
   this.title = title;
   this.author = author;
-  this.pages = pages;
+  this.pages = Number(pages);
   this.check = check;
 }
 
+function showMessage(text) {
+  const msg = document.createElement("div");
+  msg.textContent = text;
+  msg.className = "alert alert-info";
+  document.body.prepend(msg);
+  setTimeout(() => msg.remove(), 2000);
+}
+
 function render() {
-  let table = document.getElementById("display");
-  let rowsNumber = table.rows.length;
-  //delete old table
-  for (let n = rowsNumber - 1; n > 0; n-- {
-    table.deleteRow(n);
-  }
+  const table = document.getElementById("display");
+  const tbody = table.querySelector("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 = tbody.insertRow();
+    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;
-    changeBut.className = "btn btn-success";
-    wasReadCell.appendChild(changeBut);
-    let readStatus = "";
-    if (myLibrary[i].check == false) {
-      readStatus = "Yes";
-    } else {
-      readStatus = "No";
-    }
-    changeBut.innerText = readStatus;
+    const changeButton = document.createElement("button");
+    changeButton.className = "btn btn-success";
+    wasReadCell.appendChild(changeButton);
+    changeButton.innerText = myLibrary[i].check ? "Yes" : "No";
 
-    changeBut.addEventListener("click", function () {
+    changeButton.addEventListener("click", function () {
       myLibrary[i].check = !myLibrary[i].check;
       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();
+      showMessage(`You've deleted title: ${deletedTitle}`);
     });
   }
 }
