minor: document the progressProxy object

googlearchive · Oct 24, 2014 · 887f67c · 887f67c
1 parent 4d75c13
commit 887f67c
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/core-ajax.html b/core-ajax.html
@@ -259,6 +259,10 @@
       if (xhr !== this.activeRequest) {
         return;
       }
+      // We create a proxy object here because these fields
+      // on the progress event are readonly properties, which
+      // causes problems in common use cases (e.g. binding to
+      // <paper-progress> attributes).
       var progressProxy = {
         lengthComputable: progress.lengthComputable,
         loaded: progress.loaded,