Update index.md

will throw -> will throw an error

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

@@ -15,7 +15,7 @@ A service worker is an event-driven [worker](/en-US/docs/Web/API/Worker) registe
 
 Service workers run in a worker context: they therefore have no DOM access and run on a different thread to the main JavaScript that powers your app. They are non-blocking and designed to be fully asynchronous. As a consequence, APIs such as synchronous [XHR](/en-US/docs/Web/API/XMLHttpRequest) and [Web Storage](/en-US/docs/Web/API/Web_Storage_API) can't be used inside a service worker.
 
-Service workers can't import JavaScript modules dynamically, and [`import()`](/en-US/docs/Web/JavaScript/Reference/Operators/import#browser_compatibility) will throw if it is called in a service worker global scope. Static imports using the [`import`](/en-US/docs/Web/JavaScript/Reference/Statements/import) statement are allowed.
+Service workers can't import JavaScript modules dynamically, and [`import()`](/en-US/docs/Web/JavaScript/Reference/Operators/import#browser_compatibility) will throw an error if it is called in a service worker global scope. Static imports using the [`import`](/en-US/docs/Web/JavaScript/Reference/Statements/import) statement are allowed.
 
 Service workers only run over HTTPS, for security reasons. Most significantly, HTTP connections are susceptible to malicious code injection by {{Glossary("MitM", "man in the middle")}} attacks, and such attacks could be worse if allowed access to these powerful APIs. In Firefox, service worker APIs are also hidden and cannot be used when the user is in [private browsing mode](https://support.mozilla.org/en-US/kb/private-browsing-use-firefox-without-history).