--- a/mobile/android/chrome/content/JSDOMParser.js
+++ b/mobile/android/chrome/content/JSDOMParser.js
@@ -491,17 +491,22 @@
         this.childNodes[i].parentNode = null;
       }
       this.childNodes = node.childNodes;
       for (let i = this.childNodes.length; --i >= 0;) {
         this.childNodes[i].parentNode = this;
       }
     },
 
-    set textContext(text) {
+    set textContent(text) {
+      // clear parentNodes for existing children
+      for (let i = this.childNodes.length; --i >= 0;) {
+        this.childNodes[i].parentNode = null;
+      }
+
       let node = new Text();
       this.childNodes = [ node ];
       node.textContent = text;
       node.parentNode = this;
     },
 
     get textContent() {
       let text = "";