ISBN Lookup

Standalone, zero-dependency JavaScript implementation powering this tool. Free to inspect, copy, and build upon.

const input = document.getElementById('isbnInput');
  const btn = document.getElementById('lookupBtn');
  const spinner = document.getElementById('spinnerWrap');
  const errorMsg = document.getElementById('errorMsg');
  const resultWrap = document.getElementById('resultWrap');

  function formatISBN(raw) {
    const digits = raw.replace(/\D/g, '');
    if (digits.length === 13) {
      return digits.replace(/(\d{3})(\d{1})(\d{2})(\d{6})(\d{1})/, '$1-$2-$3-$4-$5');
    }
    if (digits.length === 10) {
      return digits.replace(/(\d{1})(\d{3})(\d{5})(\d{1})/, '$1-$2-$3-$4');
    }
    return raw;
  }

  input.addEventListener('input', () => {
    const pos = input.selectionStart;
    const raw = input.value.replace(/[^0-9X]/gi, '');
    const formatted = formatISBN(raw);
    input.value = formatted;
  });

  input.addEventListener('keydown', e => { if (e.key === 'Enter') doLookup(); });
  btn.addEventListener('click', doLookup);

  function tryExample(isbn) {
    input.value = formatISBN(isbn);
    doLookup();
  }

  function showError(msg) {
    spinner.classList.add('hidden');
    resultWrap.classList.add('hidden');
    errorMsg.textContent = msg;
    errorMsg.classList.remove('hidden');
  }

  function hideAll() {
    spinner.classList.add('hidden');
    errorMsg.classList.add('hidden');
    resultWrap.classList.add('hidden');
  }

  async function doLookup() {
    const raw = input.value.replace(/\D/g, '');
    if (raw.length !== 10 && raw.length !== 13) {
      showError('Please enter a valid ISBN-10 or ISBN-13.');
      return;
    }
    hideAll();
    spinner.classList.remove('hidden');

    try {
      const olData = await fetchOpenLibrary(raw);
      if (olData) {
        renderResult(olData);
        return;
      }
    } catch(e) {}

    try {
      const gbData = await fetchGoogleBooks(raw);
      if (gbData) {
        renderResult(gbData);
        return;
      }
    } catch(e) {}

    showError('Book not found. Check the ISBN and try again.');
  }

  async function fetchOpenLibrary(isbn) {
    const url = `https://openlibrary.org/api/books?bibkeys=ISBN:${isbn}&format=json&jscmd=data`;
    const res = await fetch(url);
    if (!res.ok) throw new Error('Network error');
    const json = await res.json();
    const key = `ISBN:${isbn}`;
    if (!json[key]) return null;
    const b = json[key];

    const authors = (b.authors || []).map(a => a.name).join(', ') || 'Unknown';
    const publisher = (b.publishers || []).map(p => p.name).join(', ') || null;
    const year = b.publish_date || null;
    const pages = b.number_of_pages || null;
    const subjects = (b.subjects || []).slice(0, 10).map(s => typeof s === 'string' ? s : s.name);
    const isbn13 = (b.identifiers?.isbn_13 || [])[0] || (isbn.length === 13 ? isbn : null);
    const isbn10 = (b.identifiers?.isbn_10 || [])[0] || (isbn.length === 10 ? isbn : null);
    const cover = b.cover ? (b.cover.large || b.cover.medium || b.cover.small) : null;
    const olUrl = b.url || `https://openlibrary.org/isbn/${isbn}`;
    const wcUrl = `https://www.worldcat.org/isbn/${isbn}`;

    return { title: b.title, authors, publisher, year, pages, subjects, isbn13, isbn10, cover, olUrl, wcUrl };
  }

  async function fetchGoogleBooks(isbn) {
    const url = `https://www.googleapis.com/books/v1/volumes?q=isbn:${isbn}`;
    const res = await fetch(url);
    if (!res.ok) throw new Error('Network error');
    const json = await res.json();
    if (!json.items || !json.items.length) return null;
    const vol = json.items[0].volumeInfo;

    const authors = (vol.authors || []).join(', ') || 'Unknown';
    const publisher = vol.publisher || null;
    const year = vol.publishedDate || null;
    const pages = vol.pageCount || null;
    const subjects = (vol.categories || []).slice(0, 10);
    const identifiers = vol.industryIdentifiers || [];
    const isbn13 = (identifiers.find(i => i.type === 'ISBN_13') || {}).identifier || null;
    const isbn10 = (identifiers.find(i => i.type === 'ISBN_10') || {}).identifier || null;
    const cover = vol.imageLinks ? (vol.imageLinks.thumbnail || vol.imageLinks.smallThumbnail) : null;
    const olUrl = `https://openlibrary.org/isbn/${isbn}`;
    const wcUrl = `https://www.worldcat.org/isbn/${isbn}`;

    return { title: vol.title, authors, publisher, year, pages, subjects, isbn13, isbn10, cover, olUrl, wcUrl };
  }

  function renderResult(data) {
    spinner.classList.add('hidden');

    document.getElementById('bookTitle').textContent = data.title || 'Unknown Title';
    document.getElementById('bookAuthors').textContent = data.authors || '';
    document.getElementById('bookPublisher').textContent = data.publisher || '—';
    document.getElementById('bookYear').textContent = data.year || '—';
    document.getElementById('bookPages').textContent = data.pages ? `${data.pages} pages` : '—';
    document.getElementById('bookIsbn13').textContent = data.isbn13 || '—';
    document.getElementById('bookIsbn10').textContent = data.isbn10 || '—';

    const coverImg = document.getElementById('coverImg');
    const coverPlaceholder = document.getElementById('coverPlaceholder');
    if (data.cover) {
      coverImg.src = data.cover;
      coverImg.style.display = 'block';
      coverPlaceholder.style.display = 'none';
    } else {
      coverImg.style.display = 'none';
      coverPlaceholder.style.display = 'flex';
    }

    const subjectWrap = document.getElementById('subjectWrap');
    subjectWrap.innerHTML = data.subjects.length
      ? data.subjects.map(s => `<span class="subject-tag">${s}</span>`).join('')
      : '';

    const bookLinks = document.getElementById('bookLinks');
    bookLinks.innerHTML = `
      <a class="book-link" href="${data.olUrl}" target="_blank" rel="noopener">OpenLibrary ↗</a>
      <a class="book-link" href="${data.wcUrl}" target="_blank" rel="noopener">WorldCat ↗</a>
    `;

    resultWrap.classList.remove('hidden');
  }