Lightning Locker provides component isolation and security that allows code from many sources to execute and interact using safe, standard APIs and event mechanisms. To write code that’s compatible with Locker, use Locker tools.
Lightning Web Security (LWS) is an alternative to Lightning Locker for Lightning web components. LWS is intended to replace Lightning Locker over several releases. For more information, see Lightning Web Security.
addEventListener(), use MDN.
Salesforce ended support for Internet Explorer 11 on January 1, 2023. After Winter '24, you can no longer use Internet Explorer 11 and other legacy browsers to view or access Lightning Experience.
- Leveraging the Newest ESXX Features in LWC
- Salesforce Help: Considerations for Microsoft Internet Explorer