Pagination buttons are suddenly disappearing when tried to delete some javascript code

In a commercial website I am making, I have been trying to test out the pagination buttons. But the problem is that for some reason the script that I applied to my index.html isn’t working. I am following along a youtube video and planned to work my way through that, but I encountered the following issues:

1 – When I delete code from my script.js, any code actually, it causes my pagination buttons to disappear.

<!DOCTYPE html>
<html lang="en">

    <head>
      
        <meta charset="UTF-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Tech2etc Ecommerce Tutorial</title>
       
        <link rel="stylesheet" href="https://pro.fontawesome.com/releases/v5.10.0/css/all.css" />

        <link rel="stylesheet" href="style.css">
        
        <link rel="stylesheet" href="pagination.css">

   
    </head>

    <body>


        <!-- Pagination Buttons -->

        <div class="pagination-buttons">
  <button type="button" class="page-btn prev-page">prev</button>
  <button type="button" class="page-btn start-page">start</button>
  <button type="button" class="page-btn active">1</button>
  <button type="button" class="page-btn">2</button>
  <button type="button" class="page-btn">3</button>
  <button type="button" class="page-btn">4</button>
  <button type="button" class="page-btn">5</button>
  <button type="button" class="page-btn">6</button>
  <button type="button" class="page-btn">7</button>
  <button type="button" class="page-btn">8</button>
  <button type="button" class="page-btn">9</button>
  <button type="button" class="page-btn next-page">next</button>
  <button type="button" class="page-btn end-page">end</button>
</div> 

<script src="script.js" defer>  </script>

        
    </body>

</html>

html,
body {
  width: 100%;
  height: 100%;
  margin: 0;
  font-family: sans-serif;
  padding: 25px;
  background: #fff;
  color: #111;
  display: flex;
  justify-content: center;
  align-items: center;
}

*, *::after, *::before {
  box-sizing: border-box;
}

button {
  background: none;
  appearance: none;
  -webkit-appearance: none;
  -ms-appearance: none;
  -moz-appearance: none;
  border: none;
  cursor: pointer;
}

.page-btn {
  background: #ddd;
  color: #2c303a;
  height: 35px;
  border-radius: 2px;
  padding: 0 10px;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  transition: background 0.3s ease;
  margin: 0 2px
}

.page-btn:first-of-type {
  margin-left: 0;
}

.page-btn:last-of-type {
  margin-right: 0;
}

.page-btn:not([class$="-page"]) {
  width: 35px;
}

.pagination-buttons {
  display: flex;
  align-items: center;
}

.page-btn[class*="-page"] {
  background: #ccc;
  font-size: 0.6em;
  font-weight: 700;
}

.page-btn.active {
  background: #717790;
  color: #fff;
}

.page-btn[disabled] {
  opacity: 0.3;
}

2 – I also don’t understand just how using this code: would give me an extra pagination button since I don’t really see any code that connects to the index.html containing that pagination container.

The closest seems to be this however this just creates an element, not retrieve it:

const paginationButtonContainer = document.createElement('div');
paginationButtonContainer.className = 'pagination-buttons';

const pageNumbers = (total, max, current) => {
    const half = Math.floor(max / 2);
    let to = max;
    
    if(current + half >= total) {
      to = total;
    } else if(current > half) {
      to = current + half ;
    }
    
    let from = Math.max(to - max, 0);
  
    return Array.from({length: Math.min(total, max)}, (_, i) => (i + 1) + from);
  }
  
  function PaginationButton(totalPages, maxPagesVisible = 10, currentPage = 1) {
    let pages = pageNumbers(totalPages, maxPagesVisible, currentPage);
    let currentPageBtn = null;
    const buttons = new Map();
    const disabled = {
      start: () => pages[0] === 1,
      prev: () => currentPage === 1 || currentPage > totalPages,
      end: () => pages.slice(-1)[0] === totalPages,
      next: () => currentPage >= totalPages
    }
    const frag = document.createDocumentFragment();
    const paginationButtonContainer = document.createElement('div');
    paginationButtonContainer.className = 'pagination-buttons';
    
    const createAndSetupButton = (label = '', cls = '', disabled = false, handleClick) => {
      const buttonElement = document.createElement('button');
      buttonElement.textContent = label;
      buttonElement.className = `page-btn ${cls}`;
      buttonElement.disabled = disabled;
      buttonElement.addEventListener('click', e => {
        handleClick(e);
        this.update();
        paginationButtonContainer.value = currentPage;
        paginationButtonContainer.dispatchEvent(new CustomEvent('change', {detail: {currentPageBtn}}));
      });
      
      return buttonElement;
    }
    
    const onPageButtonClick = e => currentPage = Number(e.currentTarget.textContent);
    
    const onPageButtonUpdate = index => (btn) => {
      btn.textContent = pages[index];
      
      if(pages[index] === currentPage) {
        currentPageBtn.classList.remove('active');
        btn.classList.add('active');
        currentPageBtn = btn;
        currentPageBtn.focus();
      }
    };
    
    buttons.set(
      createAndSetupButton('start', 'start-page', disabled.start(), () => currentPage = 1),
      (btn) => btn.disabled = disabled.start()
    )
    
    buttons.set(
      createAndSetupButton('prev', 'prev-page', disabled.prev(), () => currentPage -= 1),
      (btn) => btn.disabled = disabled.prev()
    )
    
    pages.map((pageNumber, index) => {
      const isCurrentPage = currentPage === pageNumber;
      const button = createAndSetupButton(
        pageNumber, isCurrentPage ? 'active' : '', false, onPageButtonClick
      );
      
      if(isCurrentPage) {
        currentPageBtn = button;
      }
      
      buttons.set(button, onPageButtonUpdate(index));
    });
    
    buttons.set(
      createAndSetupButton('next', 'next-page', disabled.next(), () => currentPage += 1),
      (btn) => btn.disabled = disabled.next()
    )
    
    buttons.set(
      createAndSetupButton('end', 'end-page', disabled.end(), () => currentPage = totalPages),
      (btn) => btn.disabled = disabled.end()
    )
    
    buttons.forEach((_, btn) => frag.appendChild(btn));
    paginationButtonContainer.appendChild(frag);
    
    this.render = (container = document.body) => {
      container.appendChild(paginationButtonContainer);
    }
    
    this.update = (newPageNumber = currentPage) => {
      currentPage = newPageNumber;
      pages = pageNumbers(totalPages, maxPagesVisible, currentPage);
      buttons.forEach((updateButton, btn) => updateButton(btn));
    }
    
    this.onChange = (handler) => {
      paginationButtonContainer.addEventListener('change', handler);
    }
  }
  
  const paginationButtons = new PaginationButton(10, 5);
  
  paginationButtons.render();
  
  paginationButtons.onChange(e => {
    console.log('-- changed', e.target.value)
  });

I tried commenting out blocks of code from the start of the script in order to figure out how the pagination button worked. I have been unable to do that however since any code that I deleted caused the buttons to keep on disappearing from my web page.

const pageNumbers = (total, max, current) => {
    const half = Math.floor(max / 2);
    let to = max;
    
    if(current + half >= total) {
      to = total;
    } else if(current > half) {
      to = current + half ;
    }
    
    let from = Math.max(to - max, 0);
  
    return Array.from({length: Math.min(total, max)}, (_, i) => (i + 1) + from);
  }
  
  function PaginationButton(totalPages, maxPagesVisible = 10, currentPage = 1) {
    let pages = pageNumbers(totalPages, maxPagesVisible, currentPage);
    let currentPageBtn = null;
    const buttons = new Map();
    const disabled = {
      start: () => pages[0] === 1,
      prev: () => currentPage === 1 || currentPage > totalPages,
      end: () => pages.slice(-1)[0] === totalPages,
      next: () => currentPage >= totalPages
    }
    const frag = document.createDocumentFragment();
    const paginationButtonContainer = document.createElement('div');
    paginationButtonContainer.className = 'pagination-buttons';
    
    const createAndSetupButton = (label = '', cls = '', disabled = false, handleClick) => {
      const buttonElement = document.createElement('button');
      buttonElement.textContent = label;
      buttonElement.className = `page-btn ${cls}`;
      buttonElement.disabled = disabled;
      buttonElement.addEventListener('click', e => {
        handleClick(e);
        this.update();
        paginationButtonContainer.value = currentPage;
        paginationButtonContainer.dispatchEvent(new CustomEvent('change', {detail: {currentPageBtn}}));
      });
      
      return buttonElement;
    }
    
    const onPageButtonClick = e => currentPage = Number(e.currentTarget.textContent);
    
    const onPageButtonUpdate = index => (btn) => {
      btn.textContent = pages[index];
      
      if(pages[index] === currentPage) {
        currentPageBtn.classList.remove('active');
        btn.classList.add('active');
        currentPageBtn = btn;
        currentPageBtn.focus();
      }
    };
    
    buttons.set(
      createAndSetupButton('start', 'start-page', disabled.start(), () => currentPage = 1),
      (btn) => btn.disabled = disabled.start()
    )
    
    buttons.set(
      createAndSetupButton('prev', 'prev-page', disabled.prev(), () => currentPage -= 1),
      (btn) => btn.disabled = disabled.prev()
    )
    
    pages.map((pageNumber, index) => {
      const isCurrentPage = currentPage === pageNumber;
      const button = createAndSetupButton(
        pageNumber, isCurrentPage ? 'active' : '', false, onPageButtonClick
      );
      
      if(isCurrentPage) {
        currentPageBtn = button;
      }
      
      buttons.set(button, onPageButtonUpdate(index));
    });
    
    buttons.set(
      createAndSetupButton('next', 'next-page', disabled.next(), () => currentPage += 1),
      (btn) => btn.disabled = disabled.next()
    )
    
    buttons.set(
      createAndSetupButton('end', 'end-page', disabled.end(), () => currentPage = totalPages),
      (btn) => btn.disabled = disabled.end()
    )
    
    buttons.forEach((_, btn) => frag.appendChild(btn));
    paginationButtonContainer.appendChild(frag);
    
    this.render = (container = document.body) => {
      container.appendChild(paginationButtonContainer);
    }
    
    this.update = (newPageNumber = currentPage) => {
      currentPage = newPageNumber;
      pages = pageNumbers(totalPages, maxPagesVisible, currentPage);
      buttons.forEach((updateButton, btn) => updateButton(btn));
    }
    
    this.onChange = (handler) => {
      paginationButtonContainer.addEventListener('change', handler);
    }
  }
  
  const paginationButtons = new PaginationButton(10, 5);
  
  paginationButtons.render();
  
  paginationButtons.onChange(e => {
    console.log('-- changed', e.target.value);
  });
  
html,
body {
  width: 100%;
  height: 100%;
  margin: 0;
  font-family: sans-serif;
  padding: 25px;
  background: #fff;
  color: #111;
  display: flex;
  justify-content: center;
  align-items: center;
}

*, *::after, *::before {
  box-sizing: border-box;
}

button {
  background: none;
  appearance: none;
  -webkit-appearance: none;
  -ms-appearance: none;
  -moz-appearance: none;
  border: none;
  cursor: pointer;
}

.page-btn {
  background: #ddd;
  color: #2c303a;
  height: 35px;
  border-radius: 2px;
  padding: 0 10px;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  transition: background 0.3s ease;
  margin: 0 2px
}

.page-btn:first-of-type {
  margin-left: 0;
}

.page-btn:last-of-type {
  margin-right: 0;
}

.page-btn:not([class$="-page"]) {
  width: 35px;
}

.pagination-buttons {
  display: flex;
  align-items: center;
}

.page-btn[class*="-page"] {
  background: #ccc;
  font-size: 0.6em;
  font-weight: 700;
}

.page-btn.active {
  background: #717790;
  color: #fff;
}

.page-btn[disabled] {
  opacity: 0.3;
}
<!DOCTYPE html>
<html lang="en">

    <head>
      
        <meta charset="UTF-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Tech2etc Ecommerce Tutorial</title>
       
        <link rel="stylesheet" href="https://pro.fontawesome.com/releases/v5.10.0/css/all.css" />

       
        <link rel="stylesheet" href="pagination.css">

   
    </head>

    <body>

        <!-- Pagination Buttons -->


    <div class="pagination-buttons">
  <button type="button" class="page-btn prev-page">prev</button>
  <button type="button" class="page-btn start-page">start</button>
  <button type="button" class="page-btn active">1</button>
  <button type="button" class="page-btn">2</button>
  <button type="button" class="page-btn">3</button>
  <button type="button" class="page-btn">4</button>
  <button type="button" class="page-btn">5</button>
  <button type="button" class="page-btn">6</button>
  <button type="button" class="page-btn">7</button>
  <button type="button" class="page-btn">8</button>
  <button type="button" class="page-btn">9</button>
  <button type="button" class="page-btn next-page">next</button>
  <button type="button" class="page-btn end-page">end</button>
</div> 


<script src="script.js" defer >  </script>

        
    </body>

</html>
const pageNumbers = (total, max, current) => {
    const half = Math.floor(max / 2);
    let to = max;
    
    if(current + half >= total) {
      to = total;
    } else if(current > half) {
      to = current + half ;
    }
    
    let from = Math.max(to - max, 0);
  
    return Array.from({length: Math.min(total, max)}, (_, i) => (i + 1) + from);
  }
  
  function PaginationButton(totalPages, maxPagesVisible = 10, currentPage = 1) {
    let pages = pageNumbers(totalPages, maxPagesVisible, currentPage);
    let currentPageBtn = null;
    const buttons = new Map();
    const disabled = {
      start: () => pages[0] === 1,
      prev: () => currentPage === 1 || currentPage > totalPages,
      end: () => pages.slice(-1)[0] === totalPages,
      next: () => currentPage >= totalPages
    }
    const frag = document.createDocumentFragment();
    const paginationButtonContainer = document.createElement('div');
    paginationButtonContainer.className = 'pagination-buttons';
    
    const createAndSetupButton = (label = '', cls = '', disabled = false, handleClick) => {
      const buttonElement = document.createElement('button');
      buttonElement.textContent = label;
      buttonElement.className = `page-btn ${cls}`;
      buttonElement.disabled = disabled;
      buttonElement.addEventListener('click', e => {
        handleClick(e);
        this.update();
        paginationButtonContainer.value = currentPage;
        paginationButtonContainer.dispatchEvent(new CustomEvent('change', {detail: {currentPageBtn}}));
      });
      
      return buttonElement;
    }
    
    const onPageButtonClick = e => currentPage = Number(e.currentTarget.textContent);
    
    const onPageButtonUpdate = index => (btn) => {
      btn.textContent = pages[index];
      
      if(pages[index] === currentPage) {
        currentPageBtn.classList.remove('active');
        btn.classList.add('active');
        currentPageBtn = btn;
        currentPageBtn.focus();
      }
    };
    
    buttons.set(
      createAndSetupButton('start', 'start-page', disabled.start(), () => currentPage = 1),
      (btn) => btn.disabled = disabled.start()
    )
    
    buttons.set(
      createAndSetupButton('prev', 'prev-page', disabled.prev(), () => currentPage -= 1),
      (btn) => btn.disabled = disabled.prev()
    )
    
    pages.map((pageNumber, index) => {
      const isCurrentPage = currentPage === pageNumber;
      const button = createAndSetupButton(
        pageNumber, isCurrentPage ? 'active' : '', false, onPageButtonClick
      );
      
      if(isCurrentPage) {
        currentPageBtn = button;
      }
      
      buttons.set(button, onPageButtonUpdate(index));
    });
    
    buttons.set(
      createAndSetupButton('next', 'next-page', disabled.next(), () => currentPage += 1),
      (btn) => btn.disabled = disabled.next()
    )
    
    buttons.set(
      createAndSetupButton('end', 'end-page', disabled.end(), () => currentPage = totalPages),
      (btn) => btn.disabled = disabled.end()
    )
    
    buttons.forEach((_, btn) => frag.appendChild(btn));
    paginationButtonContainer.appendChild(frag);
    
    this.render = (container = document.body) => {
      container.appendChild(paginationButtonContainer);
    }
    
    this.update = (newPageNumber = currentPage) => {
      currentPage = newPageNumber;
      pages = pageNumbers(totalPages, maxPagesVisible, currentPage);
      buttons.forEach((updateButton, btn) => updateButton(btn));
    }
    
    this.onChange = (handler) => {
      paginationButtonContainer.addEventListener('change', handler);
    }
  }
  
  const paginationButtons = new PaginationButton(10, 5);
  
  paginationButtons.render();
  
  paginationButtons.onChange(e => {
    console.log('-- changed', e.target.value);
  });
  
html,
body {
  width: 100%;
  height: 100%;
  margin: 0;
  font-family: sans-serif;
  padding: 25px;
  background: #fff;
  color: #111;
  display: flex;
  justify-content: center;
  align-items: center;
}

*, *::after, *::before {
  box-sizing: border-box;
}

button {
  background: none;
  appearance: none;
  -webkit-appearance: none;
  -ms-appearance: none;
  -moz-appearance: none;
  border: none;
  cursor: pointer;
}

.page-btn {
  background: #ddd;
  color: #2c303a;
  height: 35px;
  border-radius: 2px;
  padding: 0 10px;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  transition: background 0.3s ease;
  margin: 0 2px
}

.page-btn:first-of-type {
  margin-left: 0;
}

.page-btn:last-of-type {
  margin-right: 0;
}

.page-btn:not([class$="-page"]) {
  width: 35px;
}

.pagination-buttons {
  display: flex;
  align-items: center;
}

.page-btn[class*="-page"] {
  background: #ccc;
  font-size: 0.6em;
  font-weight: 700;
}

.page-btn.active {
  background: #717790;
  color: #fff;
}

.page-btn[disabled] {
  opacity: 0.3;
}
<!DOCTYPE html>
<html lang="en">

    <head>
      
        <meta charset="UTF-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Tech2etc Ecommerce Tutorial</title>
       
        <link rel="stylesheet" href="https://pro.fontawesome.com/releases/v5.10.0/css/all.css" />

       
        <link rel="stylesheet" href="pagination.css">

   
    </head>

    <body>

        <!-- Pagination Buttons -->


    <div class="pagination-buttons">
  <button type="button" class="page-btn prev-page">prev</button>
  <button type="button" class="page-btn start-page">start</button>
  <button type="button" class="page-btn active">1</button>
  <button type="button" class="page-btn">2</button>
  <button type="button" class="page-btn">3</button>
  <button type="button" class="page-btn">4</button>
  <button type="button" class="page-btn">5</button>
  <button type="button" class="page-btn">6</button>
  <button type="button" class="page-btn">7</button>
  <button type="button" class="page-btn">8</button>
  <button type="button" class="page-btn">9</button>
  <button type="button" class="page-btn next-page">next</button>
  <button type="button" class="page-btn end-page">end</button>
</div> 


<script src="script.js" defer >  </script>

        
    </body>

</html>

Edited Version (got rid of the first block of code in javascript):

  function PaginationButton(totalPages, maxPagesVisible = 10, currentPage = 1) {
    let pages = pageNumbers(totalPages, maxPagesVisible, currentPage);
    let currentPageBtn = null;
    const buttons = new Map();
    const disabled = {
      start: () => pages[0] === 1,
      prev: () => currentPage === 1 || currentPage > totalPages,
      end: () => pages.slice(-1)[0] === totalPages,
      next: () => currentPage >= totalPages
    }
    const frag = document.createDocumentFragment();
    const paginationButtonContainer = document.createElement('div');
    paginationButtonContainer.className = 'pagination-buttons';
    
    const createAndSetupButton = (label = '', cls = '', disabled = false, handleClick) => {
      const buttonElement = document.createElement('button');
      buttonElement.textContent = label;
      buttonElement.className = `page-btn ${cls}`;
      buttonElement.disabled = disabled;
      buttonElement.addEventListener('click', e => {
        handleClick(e);
        this.update();
        paginationButtonContainer.value = currentPage;
        paginationButtonContainer.dispatchEvent(new CustomEvent('change', {detail: {currentPageBtn}}));
      });
      
      return buttonElement;
    }
    
    const onPageButtonClick = e => currentPage = Number(e.currentTarget.textContent);
    
    const onPageButtonUpdate = index => (btn) => {
      btn.textContent = pages[index];
      
      if(pages[index] === currentPage) {
        currentPageBtn.classList.remove('active');
        btn.classList.add('active');
        currentPageBtn = btn;
        currentPageBtn.focus();
      }
    };
    
    buttons.set(
      createAndSetupButton('start', 'start-page', disabled.start(), () => currentPage = 1),
      (btn) => btn.disabled = disabled.start()
    )
    
    buttons.set(
      createAndSetupButton('prev', 'prev-page', disabled.prev(), () => currentPage -= 1),
      (btn) => btn.disabled = disabled.prev()
    )
    
    pages.map((pageNumber, index) => {
      const isCurrentPage = currentPage === pageNumber;
      const button = createAndSetupButton(
        pageNumber, isCurrentPage ? 'active' : '', false, onPageButtonClick
      );
      
      if(isCurrentPage) {
        currentPageBtn = button;
      }
      
      buttons.set(button, onPageButtonUpdate(index));
    });
    
    buttons.set(
      createAndSetupButton('next', 'next-page', disabled.next(), () => currentPage += 1),
      (btn) => btn.disabled = disabled.next()
    )
    
    buttons.set(
      createAndSetupButton('end', 'end-page', disabled.end(), () => currentPage = totalPages),
      (btn) => btn.disabled = disabled.end()
    )
    
    buttons.forEach((_, btn) => frag.appendChild(btn));
    paginationButtonContainer.appendChild(frag);
    
    this.render = (container = document.body) => {
      container.appendChild(paginationButtonContainer);
    }
    
    this.update = (newPageNumber = currentPage) => {
      currentPage = newPageNumber;
      pages = pageNumbers(totalPages, maxPagesVisible, currentPage);
      buttons.forEach((updateButton, btn) => updateButton(btn));
    }
    
    this.onChange = (handler) => {
      paginationButtonContainer.addEventListener('change', handler);
    }
  }
  
  const paginationButtons = new PaginationButton(10, 5);
  
  paginationButtons.render();
  
  paginationButtons.onChange(e => {
    console.log('-- changed', e.target.value);
  });
  
html,
body {
  width: 100%;
  height: 100%;
  margin: 0;
  font-family: sans-serif;
  padding: 25px;
  background: #fff;
  color: #111;
  display: flex;
  justify-content: center;
  align-items: center;
}

*, *::after, *::before {
  box-sizing: border-box;
}

button {
  background: none;
  appearance: none;
  -webkit-appearance: none;
  -ms-appearance: none;
  -moz-appearance: none;
  border: none;
  cursor: pointer;
}

.page-btn {
  background: #ddd;
  color: #2c303a;
  height: 35px;
  border-radius: 2px;
  padding: 0 10px;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  transition: background 0.3s ease;
  margin: 0 2px
}

.page-btn:first-of-type {
  margin-left: 0;
}

.page-btn:last-of-type {
  margin-right: 0;
}

.page-btn:not([class$="-page"]) {
  width: 35px;
}

.pagination-buttons {
  display: flex;
  align-items: center;
}

.page-btn[class*="-page"] {
  background: #ccc;
  font-size: 0.6em;
  font-weight: 700;
}

.page-btn.active {
  background: #717790;
  color: #fff;
}

.page-btn[disabled] {
  opacity: 0.3;
}
<!DOCTYPE html>
<html lang="en">

    <head>
      
        <meta charset="UTF-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Tech2etc Ecommerce Tutorial</title>
       
        <link rel="stylesheet" href="https://pro.fontawesome.com/releases/v5.10.0/css/all.css" />

       
        <link rel="stylesheet" href="pagination.css">

   
    </head>

    <body>

        <!-- Pagination Buttons -->


    <div class="pagination-buttons">
  <button type="button" class="page-btn prev-page">prev</button>
  <button type="button" class="page-btn start-page">start</button>
  <button type="button" class="page-btn active">1</button>
  <button type="button" class="page-btn">2</button>
  <button type="button" class="page-btn">3</button>
  <button type="button" class="page-btn">4</button>
  <button type="button" class="page-btn">5</button>
  <button type="button" class="page-btn">6</button>
  <button type="button" class="page-btn">7</button>
  <button type="button" class="page-btn">8</button>
  <button type="button" class="page-btn">9</button>
  <button type="button" class="page-btn next-page">next</button>
  <button type="button" class="page-btn end-page">end</button>
</div> 


<script src="script.js" defer >  </script>

        
    </body>

</html>
  • javascript
  • html
  • css

4

When you delete code from your script.js, if the pagination buttons disappear, it’s likely that the missing code is crucial for the buttons’ functionality or rendering.

From the code you shared ensure that these methods are being called correctly. The render() method appends the buttons to the container, and update() updates their state. If these methods are not functioning as expected due to missing code, the buttons might not show up.

Here’s a simplified version of how you might ensure the pagination buttons are correctly displayed:

class PaginationButton {
  constructor(totalPages, maxPagesVisible = 10, currentPage = 1) {
    this.totalPages = totalPages;
    this.maxPagesVisible = maxPagesVisible;
    this.currentPage = currentPage;
    this.buttons = new Map();
    this.createButtons();
  }

  createButtons() {
    const container = document.createElement('div');
    container.className = 'pagination-buttons';

    const createButton = (label, cls, disabled, onClick) => {
      const button = document.createElement('button');
      button.textContent = label;
      button.className = `page-btn ${cls}`;
      button.disabled = disabled;
      button.addEventListener('click', onClick);
      return button;
    };

    container.appendChild(createButton('start', 'start-page', this.currentPage === 1, () => this.currentPage = 1));
    container.appendChild(createButton('prev', 'prev-page', this.currentPage === 1, () => this.currentPage -= 1));
    
    for (let i = 1; i <= this.totalPages; i++) {
      container.appendChild(createButton(i, i === this.currentPage ? 'active' : '', false, () => this.currentPage = i));
    }

    container.appendChild(createButton('next', 'next-page', this.currentPage === this.totalPages, () => this.currentPage += 1));
    container.appendChild(createButton('end', 'end-page', this.currentPage === this.totalPages, () => this.currentPage = this.totalPages));

    document.body.appendChild(container);
  }
}

const pagination = new PaginationButton(10, 5);

By carefully checking these aspects, you should be able to identify why the pagination buttons are disappearing and how to fix it.

1

Trang chủ Giới thiệu Sinh nhật bé trai Sinh nhật bé gái Tổ chức sự kiện Biểu diễn giải trí Dịch vụ khác Trang trí tiệc cưới Tổ chức khai trương Tư vấn dịch vụ Thư viện ảnh Tin tức - sự kiện Liên hệ Chú hề sinh nhật Trang trí YEAR END PARTY công ty Trang trí tất niên cuối năm Trang trí tất niên xu hướng mới nhất Trang trí sinh nhật bé trai Hải Đăng Trang trí sinh nhật bé Khánh Vân Trang trí sinh nhật Bích Ngân Trang trí sinh nhật bé Thanh Trang Thuê ông già Noel phát quà Biểu diễn xiếc khỉ Xiếc quay đĩa Dịch vụ tổ chức sự kiện 5 sao Thông tin về chúng tôi Dịch vụ sinh nhật bé trai Dịch vụ sinh nhật bé gái Sự kiện trọn gói Các tiết mục giải trí Dịch vụ bổ trợ Tiệc cưới sang trọng Dịch vụ khai trương Tư vấn tổ chức sự kiện Hình ảnh sự kiện Cập nhật tin tức Liên hệ ngay Thuê chú hề chuyên nghiệp Tiệc tất niên cho công ty Trang trí tiệc cuối năm Tiệc tất niên độc đáo Sinh nhật bé Hải Đăng Sinh nhật đáng yêu bé Khánh Vân Sinh nhật sang trọng Bích Ngân Tiệc sinh nhật bé Thanh Trang Dịch vụ ông già Noel Xiếc thú vui nhộn Biểu diễn xiếc quay đĩa Dịch vụ tổ chức tiệc uy tín Khám phá dịch vụ của chúng tôi Tiệc sinh nhật cho bé trai Trang trí tiệc cho bé gái Gói sự kiện chuyên nghiệp Chương trình giải trí hấp dẫn Dịch vụ hỗ trợ sự kiện Trang trí tiệc cưới đẹp Khởi đầu thành công với khai trương Chuyên gia tư vấn sự kiện Xem ảnh các sự kiện đẹp Tin mới về sự kiện Kết nối với đội ngũ chuyên gia Chú hề vui nhộn cho tiệc sinh nhật Ý tưởng tiệc cuối năm Tất niên độc đáo Trang trí tiệc hiện đại Tổ chức sinh nhật cho Hải Đăng Sinh nhật độc quyền Khánh Vân Phong cách tiệc Bích Ngân Trang trí tiệc bé Thanh Trang Thuê dịch vụ ông già Noel chuyên nghiệp Xem xiếc khỉ đặc sắc Xiếc quay đĩa thú vị

Filed under: Kiến thức lập trình - @ 01:58

Thẻ:

Trang chủ Giới thiệu Sinh nhật bé trai Sinh nhật bé gái Tổ chức sự kiện Biểu diễn giải trí Dịch vụ khác Trang trí tiệc cưới Tổ chức khai trương Tư vấn dịch vụ Thư viện ảnh Tin tức - sự kiện Liên hệ Chú hề sinh nhật Trang trí YEAR END PARTY công ty Trang trí tất niên cuối năm Trang trí tất niên xu hướng mới nhất Trang trí sinh nhật bé trai Hải Đăng Trang trí sinh nhật bé Khánh Vân Trang trí sinh nhật Bích Ngân Trang trí sinh nhật bé Thanh Trang Thuê ông già Noel phát quà Biểu diễn xiếc khỉ Xiếc quay đĩa
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