fix README documentation of error handlers

README.md

@@ -165,11 +165,11 @@ The `initProgressBar` function takes an optional object of options. The followin
 | resultElement | Override the *element* used for the result. If specified, resultElementId will be ignored. | document.getElementById(resultElementId) |
 | onProgress | function to call when progress is updated | CeleryProgressBar.onProgressDefault |
 | onSuccess | function to call when progress successfully completes | CeleryProgressBar.onSuccessDefault |
-| onError | function to call when on a known error with no specified handler | CeleryProgressBar.onErrorDefault |
+| onError | function to call on a known error with no specified handler | CeleryProgressBar.onErrorDefault |
 | onTaskError | function to call when progress completes with an error | onError |
 | onNetworkError | function to call on a network error (ignored by WebSocket) | onError |
 | onHttpError | function to call on a non-200 response (ignored by WebSocket) | onError |
-| onDataError | function to call on a 200 response that's not JSON or has invalid schema due to a programming error | onError (ignored by WebSocket) |
+| onDataError | function to call on a 200 response that's not JSON or has invalid schema due to a programming error (ignored by WebSocket) | onError |
 | onResult | function to call when returned non empty result | CeleryProgressBar.onResultDefault |