> For the complete documentation index, see [llms.txt](https://docs.apryse.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.apryse.com/web/get-started/samples/showcase-demo-multi-tab-support.md).

# Multi-Tab Support Showcase Demo Code Sample

Launch and manage multiple documents concurrently across multiple tabs using our code sample for the Apryse WebViewer SDK.

{% hint style="info" %}
**Requirements**

*These packages are required to use these features in production. Trial keys have unlimited access to all features*

<a href="/web/get-started/readme.md" class="button primary">Web SDK</a><a href="https://showcase.apryse.com/multi-tab-support" class="button primary">Live demo</a>
{% endhint %}

Easily launch and manage multiple documents concurrently with optimized performance across multiple tabs.

This demo allows you to:

* Load multiple PDFs in their own tab
* Edit each PDF file independently
* Download the updated PDFs

**Implementation steps** To add multi-tab capability to WebViewer:

Step 1: [Get started with WebViewer](/web/get-started/readme.md) in your preferred web stack Step 2: Add the ES6 JavaScript sample code provided in this guide

Once you generate your license key, it will automatically be included in your sample code below.

{% @apryse-license-key/apryse-license-key platform="WEB\_VIEWER" variant="compact" %}

<pre class="language-js" data-line-numbers><code class="lang-js">// ES6 Compliant Syntax
// GitHub Copilot v1, Claude Sonnet 3.5, 2025-08-11
// File: multi-tab-support/index.js

import WebViewer from '@pdftron/webviewer';

const licenseKey = '<code class="expression">visitor.claims.wvKey || "YOUR_WEBVIEWER_LICENSE_KEY"</code>';

const element = document.getElementById('viewer');
let theInstance = null;

const onLoad = async (instance) => {
  theInstance = instance;
  // Enable multi-tab support
  instance.UI.enableFeatures([instance.UI.Feature.MultiTab]);
  // Add default tabs
  instance.UI.TabManager.addTab(firstDefaultDocument.path, firstDefaultDocument.options);
  instance.UI.TabManager.addTab(secondDefaultDocument.path, secondDefaultDocument.options);
  instance.UI.TabManager.addTab(thirdDefaultDocument.path, thirdDefaultDocument.options);
  const allTabs = instance.UI.TabManager.getAllTabs();
  instance.UI.TabManager.setActiveTab(allTabs?.[0]?.id || 1);

  // Set up event listeners for tab management
  instance.UI.addEventListener(instance.UI.Events.TAB_ADDED, updateTabs);
  instance.UI.addEventListener(instance.UI.Events.TAB_DELETED, tabDeleted);
  instance.UI.addEventListener(instance.UI.Events.TAB_MOVED, tabMoved);
  instance.UI.addEventListener(instance.UI.Events.BEFORE_TAB_CHANGED, changeActiveTab);
  // Update the tabs UI (buttons to select and delete tabs)
  updateTabs();
  // Add the Add Tab button at the end of the controls container
  controlsContainer.appendChild(buttonNewTab);
};

WebViewer(
  {
    path: '/lib',
    licenseKey: licenseKey, 
    enableFilePicker: true, // Enable file picker to open files. In WebViewer -> menu icon -> Open File
  },
  element
).then((instance) => {
  onLoad(instance);
});

// UI elements corresponding to document tabs
// Each tab will have a button to select (activate) it and a button to delete it
let tabButtons = [];

// preserve the active tab ID to restore the active tab after deletion or movement
let activeTabID = -1; // -1 means no active tab

// listener for moving tab event
function tabMoved() {
  activeTabID = theInstance.UI.TabManager.getActiveTab().id;
  updateTabs();
}

// listener for tab deletion
function tabDeleted(){
  const tabManager = theInstance.UI.TabManager;
  try {
    activeTabID = tabManager.getActiveTab().id; // preserve the active tab ID if it exists
  } catch (error) {
    activeTabID = -1; // if the user deletes the active tab, we reset the active tab ID
  }
  updateTabs();
  const allTabs = tabManager.getAllTabs()
  if(allTabs.length > 1) { //force refreshing after deletion
    const saveActiveTabID = tabManager.getActiveTab().id;
    allTabs.forEach(tab => {
      if(tab.id != saveActiveTabID) {
        tabManager.setActiveTab(tab.id);
      }
    });
    tabManager.setActiveTab(saveActiveTabID);
  }
}

// common function to update the tab buttons in the UI
// This function will be called for any change affecting tabs, which includes:
// 1. After default tabs are created
// 2. When the active tab changes
// 3. When a tab is added, deleted, or moved
function updateTabs(){
  // Remove all tab elements from container and reset the array
  // Rebuilding the buttons array is an easy way to keep the buttons in sync with the tabs
  tabButtons.forEach(element => element.remove());
  tabButtons = [];
  const tabManager = theInstance.UI.TabManager;
  const allTabs = tabManager.getAllTabs();
  
  allTabs.forEach(tab => {
    // Create a button to select the tab (make it active)
    const buttonSelectTab = document.createElement('button');
    tabButtons.push(buttonSelectTab);
    buttonSelectTab.textContent = tab.options.filename;
    buttonSelectTab.className = 'btn-select';
    // The container inlucdes a line break to separate the tab buttons from the AddTab button.
    // Insert the button before the line break
    controlsContainer.insertBefore(buttonSelectTab, lineBreak);
    // Add an event handler to select the tab when clicked
    buttonSelectTab.onclick = async () => {
      theInstance.UI.TabManager.setActiveTab(tab.id);
    };
    // Create a button to delete the tab
    const buttonDelTab = document.createElement('button');
    tabButtons.push(buttonDelTab);
    buttonDelTab.textContent = 'x';
    buttonDelTab.className = 'btn-del';
    controlsContainer.insertBefore(buttonDelTab, lineBreak);
    // Add an event handler to delete the tab when clicked
    buttonDelTab.onclick = async () => {
      activeTabID = theInstance.UI.TabManager.getActiveTab().id;
      theInstance.UI.TabManager.deleteTab(tab.id);
    };
  });

  if(allTabs.length &#x3C; 1)
    return; // No tabs to display
  
  let activeTabIndex = 0;
  if(activeTabID &#x3C; 0) // if no active tab ID is preserved, try to find the active tab
  {
    try{
      activeTabIndex = allTabs.indexOf(tabManager.getActiveTab());
    } catch (error){
      // activeTabIndex will remain 0 if no active tab is found
    }
  } else {
    // If we have an active tab ID, find its index and set the button class accordingly
    activeTabIndex = allTabs.findIndex(obj => obj.id === activeTabID);
  }
  // Set the button styles based on the active tab index
  setButtonStyles(activeTabIndex);
}

// Function to set styles for the tab buttons based on the active tab index
// This function will be called whenever the active tab changes or tabs are added/deleted/moved
// It updates the class of the buttons to indicate which tab is active
function setButtonStyles(activeTabIndex) {
  tabButtons.forEach((button, index) => {
    if(index % 2 === 0){ // Only update the select buttons (even indices)
      button.className = (activeTabIndex * 2 === index) ? 'btn-active' : 'btn-select';
    }
  });
}

// Listener for tab change events
function changeActiveTab(prevTab, nextTab) {
  if (activeTabID === nextTab.id) 
    return;

  activeTabID = nextTab.id;
  const allTabs = theInstance.UI.TabManager.getAllTabs();
  const activeTabIndex = allTabs.findIndex(tab => tab.id === activeTabID);
  setButtonStyles(activeTabIndex);
}

// default documents to load
const firstDefaultDocument = {
  path: 'https://apryse.s3.amazonaws.com/public/files/samples/WebviewerDemoDoc.pdf',
  options: {
    extension: 'pdf',
    filename: 'Demo PDF',
    setActive: true,
    saveCurrentActiveTabState: true,
  },
};

const secondDefaultDocument = {
  path: 'https://apryse.s3.amazonaws.com/public/files/samples/sales_tracker.xlsx',
  options: {
    extension: 'xlsx',
    filename: 'Sales Tracker (xlsx)',
    setActive: false,
    saveCurrentActiveTabState: false,
  },
};

const thirdDefaultDocument = {
  path: 'https://apryse.s3.amazonaws.com/public/files/samples/Jupiter_Poster_Raster.png',
  options: {
    extension: 'png',
    filename: 'Jupiter Poster (PNG)',
    setActive: false,
    saveCurrentActiveTabState: false,
  },
};

// UI section
//
// Helper code to add controls to the viewer holding the buttons and dropdown
// This code creates a container for the buttons and dropdown, styles them, and adds them to the viewer

const buttonNewTab = document.createElement('button');
buttonNewTab.textContent = 'Add New Tab';

buttonNewTab.onclick = async () => {
  theInstance.UI.openElements(['OpenFileModal']);
};

// Create a break element to separate controls into two lines
const lineBreak = document.createElement('br');

// Create a container for all controls (label, dropdown, and buttons)
const controlsContainer = document.createElement('div');

buttonNewTab.className = 'btn-style';

controlsContainer.className = 'control-container';
controlsContainer.appendChild(lineBreak);
element.insertBefore(controlsContainer, element.firstChild);
</code></pre>


---

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