diff --git a/lib/client.js b/lib/client.js
index 4e03bad50..6283c0aad 100644
--- a/lib/client.js
+++ b/lib/client.js
@@ -270,6 +270,10 @@ function Response(xhr, options) {
   this.text = xhr.responseText;
   this.setStatusProperties(xhr.status);
   this.header = parseHeader(xhr.getAllResponseHeaders());
+  // getAllResponseHeaders sometimes falsely returns "" for CORS requests, but
+  // getResponseHeader still works. so we get content-type even if getting
+  // other headers fails.
+  this.header['content-type'] = xhr.getResponseHeader('content-type');
   this.setHeaderProperties(this.header);
   this.body = this.parseBody(this.text);
 }