diff --git a/src/core/operations/RegularExpression.mjs b/src/core/operations/RegularExpression.mjs
index cce65c6..d841168 100644
--- a/src/core/operations/RegularExpression.mjs
+++ b/src/core/operations/RegularExpression.mjs
@@ -240,7 +240,7 @@ function regexHighlight (input, regex, displayTotal) {
         if (groups.length) {
             title += "Groups:\n";
             for (let i = 0; i < groups.length; i++) {
-                title += `\t${i+1}: ${Utils.escapeHtml(groups[i])}\n`;
+                title += `\t${i+1}: ${Utils.escapeHtml(groups[i] || "")}\n`;
             }
         }
 
diff --git a/src/web/HTMLIngredient.mjs b/src/web/HTMLIngredient.mjs
index 59b7bec..ab7f682 100755
--- a/src/web/HTMLIngredient.mjs
+++ b/src/web/HTMLIngredient.mjs
@@ -4,6 +4,8 @@
  * @license Apache-2.0
  */
 
+import Utils from "../core/Utils";
+
 /**
  * Object to handle the creation of operation ingredients.
  */
@@ -156,7 +158,7 @@ class HTMLIngredient {
                     } else if ((m = this.value[i].name.match(/\[\/([a-z0-9 -()^]+)\]/i))) {
                         html += "</optgroup>";
                     } else {
-                        html += `<option populate-value="${this.value[i].value}">${this.value[i].name}</option>`;
+                        html += `<option populate-value="${Utils.escapeHtml(this.value[i].value)}">${this.value[i].name}</option>`;
                     }
                 }
                 html += `</select>