Handle readyState in submitRequest function

CHANGELOG.md

@@ -1,3 +1,8 @@
+## 5.9.2
+
+- Handle `xhr.readyState` in the `submitRequest` function and don't attempt to
+  send if it's not `1` (OPENED). (thanks to @bobbysmith007)
+
 ## 5.9.1
 
 - Fix the way upload progress is calculated when using chunked uploads. (thanks

package.json

@@ -1,6 +1,6 @@
 {
   "name": "dropzone",
-  "version": "5.9.1",
+  "version": "5.9.2",
   "description": "Handles drag and drop of files for you.",
   "keywords": [
     "dragndrop",

src/dropzone.js

@@ -1648,6 +1648,12 @@ export default class Dropzone extends Emitter {
   }
 
   submitRequest(xhr, formData, files) {
+    if (xhr.readyState != 1) {
+      console.warn(
+        "Cannot send this request because the XMLHttpRequest.readyState is not OPENED."
+      );
+      return;
+    }
     xhr.send(formData);
   }