> 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-pdf-layers.md). # PDF Layers Showcase Demo Code Sample See how to programmatically add PDF layer separation capabilities (Optional Content Groups). This code relates to our related showcase demo. {% hint style="info" %} **Requirements** *These packages are required to use these features in production. Trial keys have unlimited access to all features* Web SDKLive demo {% endhint %} Easily enable or disable layers in PDF construction drawings. This demo lets you: * Upload a PDF file of your construction drawings * Toggle individual layers (e.g., architectural, electrical) using Optional Content Groups (OCGs) * Edit layout and content directly within the PDF ### **Implementation steps** To add layer separation capability to a PDF with 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" %} 
// ES6 Compliant Syntax
// GitHub Copilot v1, Claude Sonnet 3.5, 2025-08-03
// File: pdf-layers/index.js

import WebViewer from '@pdftron/webviewer';

const licenseKey = 'visitor.claims.wvKey || "YOUR_WEBVIEWER_LICENSE_KEY"';

const element = document.getElementById('viewer');
let theInstance = null;
const onLoad = async (instance) => {
  theInstance = instance;
  instance.Core.documentViewer.addEventListener('documentLoaded', () => {
    // Initialize layers when the document is loaded
    initLayers();
  });
};

// sample PDF with multiple layers
const defaultLayersDoc = 'https://apryse.s3.us-west-1.amazonaws.com/public/files/samples/construction_drawing-final.pdf';

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

// Define variable to hold layers information
let docLayers = null;
let flatLayers = null;

// Array to hold labels, checkboxes and line breaks for layers
// This will be used to dynamically create UI elements for each layer and remove them when needed
let layerElements = [];

// Show or hide layers based on checkbox state.
// Set the value of the "visible" property for each layer in the layers array
// and update the document viewer to reflect the changes.
// The sender parameter is the actual checkbox that was changed.
// The checkbox's "value" property contains the nesting level of the layer
function updateLayersDisplay(sender) {
  // check if layer has children
  const layerLevel = +sender.value; // get the level as number
  let startCheck = false;
  let endCheck = false;
  layerElements.forEach(el => {
    if(endCheck)
      return;
    if(el.isSameNode(sender)){
      console.log("sender same as el", sender);
      startCheck = true; // found our checkbox. Start checking from next iteration
      return; // from the forEach
    }
 
    if(el.type === 'checkbox' && startCheck){
      if(+el.value <= layerLevel){ // Stop checking when we find first non-child
        endCheck = true;
        return;
      }
      // el is a child of sender. Set all children like sender
      el.checked = sender.checked; 
    }
  });
  // Following code updates the layer's visibility to match the checkboxes
  if (flatLayers && flatLayers.length > 0) {
    let checkboxIndex = 0;
    // loop to find the checkboxes, which are in the same order as their corresponding flat layers
    layerElements.forEach(el => {
      if(el.type === 'checkbox'){
        flatLayers[checkboxIndex].visible = el.checked;
        checkboxIndex++;
      }
    });
    // reflect the layers' visibility on the document
    const documentViewer = theInstance.Core.documentViewer;
    const doc = documentViewer.getDocument();
    doc.setLayersArray(flatLayers);
    documentViewer.refreshAll();
    documentViewer.updateView();
  }
}

// Retrieve the layers from the document and initialize the UI.
// This function will be called when the document is loaded and will populate
// the layers array with the document's layers and create a checkbox for each layer
// If no layers are found, it will suggest loading the default document
async function initLayers() {
  const doc = theInstance.Core.documentViewer.getDocument();
  docLayers = await doc.getLayersArray();

  // If no layers are found, suggest loading the default document
  if(doc.getType() !== 'pdf') {
    labelLayers.textContent = `This sample only supports PDFs. Click "${buttonDefault.textContent}" to load a sample with layers.`;
  } else if(!docLayers || docLayers.length === 0){
    labelLayers.textContent = `This document has no layers. Click "${buttonDefault.textContent}" to load a sample with layers.`;
  }

  // Clear existing labels and checkboxes if any exist from previous document
  layerElements.forEach(element => element.remove());
  layerElements = [];
  // reset the flatLayers array
  flatLayers = [];

  if(!docLayers || docLayers.length === 0) {
    return; // Exit if no layers are found
  }

  let currnetLevel = 0; // will be larger than zero for nested layers
  
  // Function to create UI elements for the layers.
  // Called recursively in case there are child (nested) layers
  function addCheckboxes(layerArray){
    layerArray.forEach((layer) => {
      flatLayers.push(layer); // Add the layer to the flatLayers array
      layer.visible = true; // Set all layers to visible by default
      const checkbox = document.createElement('input');
      checkbox.type = 'checkbox';
      checkbox.value = currnetLevel; // zero if it's not for a child layer
      // indent the child checkboxes based on their nesting level
      checkbox.style.marginLeft = "" + (currnetLevel * 15) + "px";
      checkbox.checked = layer.visible;
      // display the layer's name next to its checkbox
      const label = document.createElement('label');
      label.className = 'label-style';
      label.textContent = layer.name;
      // The container has 2 lines separated by a line break
      // Insert the labels and checkboxes before the line break
      controlsContainer.insertBefore(label, lineBreak);
      controlsContainer.insertBefore(checkbox, label);
      // separate each layer's checkbox and label from the previous layer with a new line break
      const br = document.createElement('br');
      controlsContainer.insertBefore(br, checkbox);
      // handle the change event for the checkboxes
      checkbox.onchange = () => {
        updateLayersDisplay(checkbox);
      };
      // Add the line-break, label and checkbox to the layer elements array for later reference
      layerElements.push(br);
      layerElements.push(label);
      layerElements.push(checkbox);
      if(layer.children && layer.children.length > 0) {
        // Since the layer has children, recursively add checkboxes for these child layers between the brackets
        currnetLevel++;
        addCheckboxes(layer.children);
        currnetLevel--;
      }
    });
  }
  // Add checkboxes for each layer in the layers array and create a flat array of layers
  addCheckboxes(docLayers);

  // Update the label to show the number of layers
  labelLayers.textContent = `Layers found: ${flatLayers.length}`;
}

// UI section

// Create a container for all controls (labels, buttons, checkboxes, etc.)
const controlsContainer = document.createElement('div');

const labelUpload = document.createElement('label');
labelUpload.textContent = 'Use the Open File command in the WebViewer UI menu to upload a PDF file';

// Create a button to open default PDF
const buttonDefault = document.createElement('button');
buttonDefault.textContent = 'Default Document';
buttonDefault.onclick = async () => {
  // load default PDF with layers
  theInstance.UI.loadDocument(defaultLayersDoc);
};

// Label to display layer count or suggest loading default document
const labelLayers = document.createElement('label');
labelLayers.textContent = "";

// Style the container and controls using CSS classes
controlsContainer.className = 'control-container';

buttonDefault.className = 'btn-style';
labelUpload.className = 'label-style';
labelLayers.className = 'label-style';

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

// Append all controls to the container
controlsContainer.appendChild(labelLayers);
controlsContainer.appendChild(lineBreak);
controlsContainer.appendChild(labelUpload);
controlsContainer.appendChild(buttonDefault);
// modify viewer element and its parent div to display controlsContainer with viewer side-by-side
element.parentElement.style.display = "flex";
element.style.display = "inline-block";
element.style.width = "75%";
controlsContainer.style.height = "100%";
controlsContainer.style.display = "inline-block";
controlsContainer.style.width = "25%";
// Add the controls container right before to the viewer
element.parentElement.insertBefore(controlsContainer, element);
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