diff --git a/js/aidmi_ckeditor.js b/js/aidmi_ckeditor.js
index cf2d9cdfdea0ae663f467748c9f68243be4d893a..a8f14eb2f256ac46eb9eb49072591fe27354927a 100644
--- a/js/aidmi_ckeditor.js
+++ b/js/aidmi_ckeditor.js
@@ -65,8 +65,11 @@ let aidmiEditedText;
                 existingButton.focus();
               }
               altTextField = mutation.target;
+              // Check if the alternative text form exists.
+              altTextForm = document.querySelector('.ck-text-alternative-form');
+              // Get the selected image.
               imgTag = aidmiActiveEditorInstance.data.stringify(aidmiActiveEditorInstance.model.getSelectedContent(aidmiActiveEditorInstance.model.document.selection));
-              if (altTextField) {
+              if ((altTextForm) && (altTextField) && (imgTag)) {
                 aidmiButton(altTextField, aidmiActiveEditorInstance, imgTag);
               }
             }