diff --git a/public/js/gf-giftaid-field-frontend.js b/public/js/gf-giftaid-field-frontend.js
index cadead3..654dacd 100644
--- a/public/js/gf-giftaid-field-frontend.js
+++ b/public/js/gf-giftaid-field-frontend.js
@@ -1,8 +1,9 @@
 function gfGiftAidOnInputChange(elem) {
-  if (
-    !(elem instanceof HTMLElement) ||
-    !elem.classList.contains('ginput_amount')
-  ) {
+  if (!(elem instanceof HTMLElement)) {
+    return;
+  }
+
+  if (! elem.classList.contains('ginput_total') && ! elem.classList.contains('ginput_amount')) {
     return;
   }
 
@@ -11,6 +12,11 @@ function gfGiftAidOnInputChange(elem) {
     return;
   }
 
+  const totalEl = parentForm.querySelector('.ginput_total');
+  if (totalEl instanceof HTMLElement) {
+    elem = totalEl;
+  }
+
   const spanTotal = parentForm.querySelectorAll('.gform_donation_total');
   if (!(spanTotal instanceof NodeList) || 0 === spanTotal.length) {
     return;