diff --git a/app/assets/javascripts/copy_as_gfm.js.es6 b/app/assets/javascripts/copy_as_gfm.js.es6
index 0d1e9b0a952..63291853548 100644
--- a/app/assets/javascripts/copy_as_gfm.js.es6
+++ b/app/assets/javascripts/copy_as_gfm.js.es6
@@ -231,20 +231,13 @@
       let clipboardData = e.originalEvent.clipboardData;
       if (!clipboardData) return;
 
-      if (!window.getSelection) return;
-
-      let selection = window.getSelection();
-      if (!selection.rangeCount || selection.rangeCount === 0) return;
-
-      let selectedDocument = selection.getRangeAt(0).cloneContents();
-      if (!selectedDocument) return;
-
-      if (selectedDocument.textContent.length === 0) return;
+      let documentFragment = CopyAsGFM.getSelectedFragment();
+      if (!documentFragment) return;
 
       e.preventDefault();
-      clipboardData.setData('text/plain', selectedDocument.textContent);
+      clipboardData.setData('text/plain', documentFragment.textContent);
 
-      let gfm = CopyAsGFM.nodeToGFM(selectedDocument);
+      let gfm = CopyAsGFM.nodeToGFM(documentFragment);
       clipboardData.setData('text/x-gfm', gfm);
     }
 
@@ -257,11 +250,25 @@
 
       e.preventDefault();
 
-      this.insertText(e.target, gfm);
+      CopyAsGFM.insertText(e.target, gfm);
     }
 
-    insertText(target, text) {
-      // Firefox doesn't support `document.execCommand('insertText', false, text);` on textareas
+    static getSelectedFragment() {
+      if (!window.getSelection) return null;
+
+      let selection = window.getSelection();
+      if (!selection.rangeCount || selection.rangeCount === 0) return null;
+
+      let documentFragment = selection.getRangeAt(0).cloneContents();
+      if (!documentFragment) return null;
+
+      if (documentFragment.textContent.length === 0) return null;
+
+      return documentFragment;
+    }
+
+    static insertText(target, text) {
+      // Firefox doesn't support `document.execCommand('insertText', false, text)` on textareas
 
       let selectionStart = target.selectionStart;
       let selectionEnd = target.selectionEnd;
@@ -292,7 +299,7 @@
         for (let selector in rules) {
           let func = rules[selector];
 
-          if (!node.matches(selector)) continue;
+          if (!CopyAsGFM.nodeMatchesSelector(node, selector)) continue;
 
           let result = func(node, text);
           if (result === false) continue;
@@ -315,11 +322,38 @@
         let clonedNode = clonedNodes[i];
 
         let text = this.nodeToGFM(node);
+        
+        // `clonedNode.replaceWith(text)` is not yet widely supported
         clonedNode.parentNode.replaceChild(document.createTextNode(text), clonedNode);
       }
 
       return clonedParentNode.innerText || clonedParentNode.textContent;
     }
+
+    static nodeMatchesSelector(node, selector) {
+      let matches = Element.prototype.matches ||
+        Element.prototype.matchesSelector ||
+        Element.prototype.mozMatchesSelector ||
+        Element.prototype.msMatchesSelector ||
+        Element.prototype.oMatchesSelector ||
+        Element.prototype.webkitMatchesSelector;
+
+      if (matches) {
+        return matches.call(node, selector);
+      }
+
+      // IE11 doesn't support `node.matches(selector)`
+
+      let parentNode = node.parentNode;
+      if (!parentNode) {
+        parentNode = document.createElement('div');
+        node = node.cloneNode(true);
+        parentNode.appendChild(node);
+      }
+
+      let matchingNodes = parentNode.querySelectorAll(selector);
+      return Array.prototype.indexOf.call(matchingNodes, node) !== -1;
+    }
   }
 
   window.gl = window.gl || {};
diff --git a/app/assets/javascripts/shortcuts_issuable.js b/app/assets/javascripts/shortcuts_issuable.js
index 426821873d7..e9ede122ab7 100644
--- a/app/assets/javascripts/shortcuts_issuable.js
+++ b/app/assets/javascripts/shortcuts_issuable.js
@@ -39,26 +39,22 @@
     }
 
     ShortcutsIssuable.prototype.replyWithSelectedText = function() {
-      var quote, replyField, selectedDocument, selected, selection, separator;
-      if (!window.getSelection) return;
+      var quote, replyField, documentFragment, selected, separator;
 
-      selection = window.getSelection();
-      if (!selection.rangeCount || selection.rangeCount === 0) return;
+      documentFragment = window.gl.CopyAsGFM.getSelectedFragment();
+      if (!documentFragment) return;
 
-      selectedDocument = selection.getRangeAt(0).cloneContents();
-      if (!selectedDocument) return;
-
-      selected = window.gl.CopyAsGFM.nodeToGFM(selectedDocument);
+      selected = window.gl.CopyAsGFM.nodeToGFM(documentFragment);
 
       replyField = $('.js-main-target-form #note_note');
       if (selected.trim() === "") {
         return;
       }
       quote = _.map(selected.split("\n"), function(val) {
-        return "> " + val + "\n";
+        return ("> " + val).trim() + "\n";
       });
       // If replyField already has some content, add a newline before our quote
-      separator = replyField.val().trim() !== "" && "\n" || '';
+      separator = replyField.val().trim() !== "" && "\n\n" || '';
       replyField.val(function(_, current) {
         return current + separator + quote.join('') + "\n";
       });
diff --git a/spec/javascripts/shortcuts_issuable_spec.js b/spec/javascripts/shortcuts_issuable_spec.js
index ae5d639ad9c..7e5c0e2f144 100644
--- a/spec/javascripts/shortcuts_issuable_spec.js
+++ b/spec/javascripts/shortcuts_issuable_spec.js
@@ -1,6 +1,7 @@
 /* eslint-disable space-before-function-paren, no-return-assign, no-var, quotes, padded-blocks */
 /* global ShortcutsIssuable */
 
+/*= require copy_as_gfm */
 /*= require shortcuts_issuable */
 
 (function() {
@@ -14,10 +15,12 @@
     });
     return describe('#replyWithSelectedText', function() {
       var stubSelection;
-      // Stub window.getSelection to return the provided String.
-      stubSelection = function(text) {
-        return window.getSelection = function() {
-          return text;
+      // Stub window.gl.CopyAsGFM.getSelectedFragment to return a node with the provided HTML.
+      stubSelection = function(html) {
+        window.gl.CopyAsGFM.getSelectedFragment = function() {
+          var node = document.createElement('div');
+          node.innerHTML = html;
+          return node;
         };
       };
       beforeEach(function() {
@@ -32,13 +35,13 @@
       });
       describe('with any selection', function() {
         beforeEach(function() {
-          return stubSelection('Selected text.');
+          return stubSelection('<p>Selected text.</p>');
         });
         it('leaves existing input intact', function() {
           $(this.selector).val('This text was already here.');
           expect($(this.selector).val()).toBe('This text was already here.');
           this.shortcut.replyWithSelectedText();
-          return expect($(this.selector).val()).toBe("This text was already here.\n> Selected text.\n\n");
+          return expect($(this.selector).val()).toBe("This text was already here.\n\n> Selected text.\n\n");
         });
         it('triggers `input`', function() {
           var triggered;
@@ -61,16 +64,16 @@
       });
       describe('with a one-line selection', function() {
         return it('quotes the selection', function() {
-          stubSelection('This text has been selected.');
+          stubSelection('<p>This text has been selected.</p>');
           this.shortcut.replyWithSelectedText();
           return expect($(this.selector).val()).toBe("> This text has been selected.\n\n");
         });
       });
       return describe('with a multi-line selection', function() {
         return it('quotes the selected lines as a group', function() {
-          stubSelection("Selected line one.\n\nSelected line two.\nSelected line three.\n");
+          stubSelection("<p>Selected line one.</p>\n\n<p>Selected line two.</p>\n\n<p>Selected line three.</p>");
           this.shortcut.replyWithSelectedText();
-          return expect($(this.selector).val()).toBe("> Selected line one.\n> Selected line two.\n> Selected line three.\n\n");
+          return expect($(this.selector).val()).toBe("> Selected line one.\n>\n> Selected line two.\n>\n> Selected line three.\n\n");
         });
       });
     });