diff --git a/dom/inputmethod/forms.js b/dom/inputmethod/forms.js
index b9a33b32824e..089c9ba1e077 100644
--- a/dom/inputmethod/forms.js
+++ b/dom/inputmethod/forms.js
@@ -1277,14 +1277,7 @@ let CompositionManager =  {
     if (!this._isStarted) {
       return;
     }
-    // Update the composing text.
-    let compositionString = domWindowUtils.createCompositionStringSynthesizer();
-    compositionString.setString(text);
-    // Set the cursor position to |text.length| so that the text will be
-    // committed before the cursor position.
-    compositionString.setCaret(text.length, 0);
-    compositionString.dispatchEvent();
-    domWindowUtils.sendCompositionEvent('compositionend', text, '');
+    domWindowUtils.sendCompositionEvent('compositioncommit', text, '');
     this._isStarted = false;
   },