Add docs for ErrorEvent.error (#36305)

add docs for `ErrorEvent.error`

files/en-us/web/api/errorevent/error/index.md

@@ -0,0 +1,31 @@
+---
+title: "ErrorEvent: error property"
+short-title: error
+slug: Web/API/ErrorEvent/error
+page-type: web-api-instance-property
+browser-compat: api.ErrorEvent.error
+---
+
+{{APIRef("HTML DOM")}}{{AvailableInWorkers}}
+
+The **`error`** read-only property of the {{domxref("ErrorEvent")}} interface returns a JavaScript value, such as an {{jsxref("Error")}} or {{domxref("DOMException")}}, representing the error associated with this event.
+
+## Value
+
+Any valid JavaScript value.
+
+## Examples
+
+```js
+window.addEventListener("error", (ev) => {
+  console.log("The error instance: " + ev.error);
+});
+```
+
+## Specifications
+
+{{Specifications}}
+
+## Browser compatibility
+
+{{Compat}}

files/en-us/web/api/errorevent/index.md

@@ -29,7 +29,7 @@ _Also inherits properties from its parent {{domxref("Event")}}_.
 - {{domxref("ErrorEvent.colno")}} {{ReadOnlyInline}}
   - : An `integer` containing the column number of the script file on which the error occurred.
 - {{domxref("ErrorEvent.error")}} {{ReadOnlyInline}}
-  - : A JavaScript `Object` that is concerned by the event.
+  - : A JavaScript value, such as an {{jsxref("Error")}} or {{domxref("DOMException")}}, representing the error associated with this event.
 
 ## Instance methods