diff --git a/bower.json b/bower.json
index c90590ff7..c3aa08151 100644
--- a/bower.json
+++ b/bower.json
@@ -1,6 +1,6 @@
 {
   "name": "pdfjs-dist",
-  "version": "1.3.133",
+  "version": "1.3.135",
   "main": [
     "build/pdf.js",
     "build/pdf.worker.js"
diff --git a/build/pdf.combined.js b/build/pdf.combined.js
index 191f581e1..f2ab82b02 100644
--- a/build/pdf.combined.js
+++ b/build/pdf.combined.js
@@ -21,8 +21,8 @@ if (typeof PDFJS === 'undefined') {
    typeof global !== 'undefined' ? global : this).PDFJS = {};
 }
 
-PDFJS.version = '1.3.133';
-PDFJS.build = '8558948';
+PDFJS.version = '1.3.135';
+PDFJS.build = 'b32cdf5';
 
 (function pdfjsWrapper() {
   // Use strict in our context only - users might not want it
@@ -1846,6 +1846,9 @@ AnnotationElementFactory.prototype =
       case AnnotationType.POPUP:
         return new PopupAnnotationElement(parameters);
 
+      case AnnotationType.UNDERLINE:
+        return new UnderlineAnnotationElement(parameters);
+
       default:
         throw new Error('Unimplemented annotation type "' + subtype + '"');
     }
@@ -2374,6 +2377,33 @@ var PopupElement = (function PopupElementClosure() {
   return PopupElement;
 })();
 
+/**
+ * @class
+ * @alias UnderlineAnnotationElement
+ */
+var UnderlineAnnotationElement = (
+    function UnderlineAnnotationElementClosure() {
+  function UnderlineAnnotationElement(parameters) {
+    AnnotationElement.call(this, parameters);
+  }
+
+  Util.inherit(UnderlineAnnotationElement, AnnotationElement, {
+    /**
+     * Render the underline annotation's HTML element in the empty container.
+     *
+     * @public
+     * @memberof UnderlineAnnotationElement
+     * @returns {HTMLSectionElement}
+     */
+    render: function UnderlineAnnotationElement_render() {
+      this.container.className = 'underlineAnnotation';
+      return this.container;
+    }
+  });
+
+  return UnderlineAnnotationElement;
+})();
+
 /**
  * @typedef {Object} AnnotationLayerParameters
  * @property {PageViewport} viewport
@@ -46542,6 +46572,9 @@ AnnotationFactory.prototype = /** @lends AnnotationFactory.prototype */ {
       case 'Popup':
         return new PopupAnnotation(parameters);
 
+      case 'Underline':
+        return new UnderlineAnnotation(parameters);
+
       default:
         warn('Unimplemented annotation type "' + subtype + '", ' +
              'falling back to base annotation');
@@ -47232,6 +47265,22 @@ var PopupAnnotation = (function PopupAnnotationClosure() {
   return PopupAnnotation;
 })();
 
+var UnderlineAnnotation = (function UnderlineAnnotationClosure() {
+  function UnderlineAnnotation(parameters) {
+    Annotation.call(this, parameters);
+
+    this.data.annotationType = AnnotationType.UNDERLINE;
+    this.data.hasHtml = true;
+
+    // PDF viewers completely ignore any border styles.
+    this.data.borderStyle.setWidth(0);
+  }
+
+  Util.inherit(UnderlineAnnotation, Annotation, {});
+
+  return UnderlineAnnotation;
+})();
+
 exports.Annotation = Annotation;
 exports.AnnotationBorderStyle = AnnotationBorderStyle;
 exports.AnnotationFactory = AnnotationFactory;
diff --git a/build/pdf.js b/build/pdf.js
index 40285308d..1b0fc734b 100644
--- a/build/pdf.js
+++ b/build/pdf.js
@@ -21,8 +21,8 @@ if (typeof PDFJS === 'undefined') {
    typeof global !== 'undefined' ? global : this).PDFJS = {};
 }
 
-PDFJS.version = '1.3.133';
-PDFJS.build = '8558948';
+PDFJS.version = '1.3.135';
+PDFJS.build = 'b32cdf5';
 
 (function pdfjsWrapper() {
   // Use strict in our context only - users might not want it
@@ -1846,6 +1846,9 @@ AnnotationElementFactory.prototype =
       case AnnotationType.POPUP:
         return new PopupAnnotationElement(parameters);
 
+      case AnnotationType.UNDERLINE:
+        return new UnderlineAnnotationElement(parameters);
+
       default:
         throw new Error('Unimplemented annotation type "' + subtype + '"');
     }
@@ -2374,6 +2377,33 @@ var PopupElement = (function PopupElementClosure() {
   return PopupElement;
 })();
 
+/**
+ * @class
+ * @alias UnderlineAnnotationElement
+ */
+var UnderlineAnnotationElement = (
+    function UnderlineAnnotationElementClosure() {
+  function UnderlineAnnotationElement(parameters) {
+    AnnotationElement.call(this, parameters);
+  }
+
+  Util.inherit(UnderlineAnnotationElement, AnnotationElement, {
+    /**
+     * Render the underline annotation's HTML element in the empty container.
+     *
+     * @public
+     * @memberof UnderlineAnnotationElement
+     * @returns {HTMLSectionElement}
+     */
+    render: function UnderlineAnnotationElement_render() {
+      this.container.className = 'underlineAnnotation';
+      return this.container;
+    }
+  });
+
+  return UnderlineAnnotationElement;
+})();
+
 /**
  * @typedef {Object} AnnotationLayerParameters
  * @property {PageViewport} viewport
diff --git a/build/pdf.worker.js b/build/pdf.worker.js
index eee5b5035..d34ae13a0 100644
--- a/build/pdf.worker.js
+++ b/build/pdf.worker.js
@@ -21,8 +21,8 @@ if (typeof PDFJS === 'undefined') {
    typeof global !== 'undefined' ? global : this).PDFJS = {};
 }
 
-PDFJS.version = '1.3.133';
-PDFJS.build = '8558948';
+PDFJS.version = '1.3.135';
+PDFJS.build = 'b32cdf5';
 
 (function pdfjsWrapper() {
   // Use strict in our context only - users might not want it
@@ -38853,6 +38853,9 @@ AnnotationFactory.prototype = /** @lends AnnotationFactory.prototype */ {
       case 'Popup':
         return new PopupAnnotation(parameters);
 
+      case 'Underline':
+        return new UnderlineAnnotation(parameters);
+
       default:
         warn('Unimplemented annotation type "' + subtype + '", ' +
              'falling back to base annotation');
@@ -39543,6 +39546,22 @@ var PopupAnnotation = (function PopupAnnotationClosure() {
   return PopupAnnotation;
 })();
 
+var UnderlineAnnotation = (function UnderlineAnnotationClosure() {
+  function UnderlineAnnotation(parameters) {
+    Annotation.call(this, parameters);
+
+    this.data.annotationType = AnnotationType.UNDERLINE;
+    this.data.hasHtml = true;
+
+    // PDF viewers completely ignore any border styles.
+    this.data.borderStyle.setWidth(0);
+  }
+
+  Util.inherit(UnderlineAnnotation, Annotation, {});
+
+  return UnderlineAnnotation;
+})();
+
 exports.Annotation = Annotation;
 exports.AnnotationBorderStyle = AnnotationBorderStyle;
 exports.AnnotationFactory = AnnotationFactory;
diff --git a/package.json b/package.json
index 459a5e589..fb9600964 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "pdfjs-dist",
-  "version": "1.3.133",
+  "version": "1.3.135",
   "main": "build/pdf.js",
   "description": "Generic build of Mozilla's PDF.js library.",
   "keywords": [
diff --git a/web/pdf_viewer.css b/web/pdf_viewer.css
index 2783c1bea..96e09ce08 100644
--- a/web/pdf_viewer.css
+++ b/web/pdf_viewer.css
@@ -138,6 +138,10 @@
   padding-top: 0.2em;
 }
 
+.annotationLayer .underlineAnnotation {
+  cursor: pointer;
+}
+
 .pdfViewer .canvasWrapper {
   overflow: hidden;
 }