Remove unnecessary code (#36099)

* Update index.md

* Update files/en-us/web/api/eventtarget/addeventlistener/index.md

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

* Update index.md

* Update index.md

* Update index.md

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Joshua Chen <[email protected]>

files/en-us/web/api/eventtarget/addeventlistener/index.md

@@ -133,80 +133,6 @@ function handleEvent(event) {
 }
 ```
 
-### Safely detecting option support
-
-In older versions of the DOM specification, the third parameter of
-`addEventListener()` was a Boolean value indicating whether or not to use
-capture. Over time, it became clear that more options were needed. Rather than adding
-more parameters to the function (complicating things enormously when dealing with
-optional values), the third parameter was changed to an object that can contain various
-properties defining the values of options to configure the process of removing the event
-listener.
-
-Because older browsers (as well as some not-too-old browsers) still assume the third
-parameter is a Boolean, you need to build your code to handle this scenario
-intelligently. You can do this by using feature detection for each of the options you're
-interested in.
-
-For example, if you want to check for the `passive` option:
-
-```js
-let passiveSupported = false;
-
-try {
-  const options = {
-    get passive() {
-      // This function will be called when the browser
-      // attempts to access the passive property.
-      passiveSupported = true;
-      return false;
-    },
-  };
-
-  window.addEventListener("test", null, options);
-  window.removeEventListener("test", null, options);
-} catch (err) {
-  passiveSupported = false;
-}
-```
-
-This creates an `options` object with a getter function for the
-`passive` property; the getter sets a flag,
-`passiveSupported`, to `true` if it gets called. That
-means that if the browser checks the value of the `passive` property on the
-`options` object, `passiveSupported` will be
-set to `true`; otherwise, it will remain `false`. We then call
-`addEventListener()` to set up a fake event handler, specifying those
-options, so that the options will be checked if the browser recognizes an object as the
-third parameter. Then, we call [`removeEventListener()`](/en-US/docs/Web/API/EventTarget/removeEventListener) to clean up after
-ourselves. (Note that `handleEvent()` is ignored on event listeners that
-aren't called.)
-
-You can check whether any option is supported this way. Just add a getter for that
-option using code similar to what is shown above.
-
-Then, when you want to create an actual event listener that uses the options in
-question, you can do something like this:
-
-```js
-someElement.addEventListener(
-  "mouseup",
-  handleMouseUp,
-  passiveSupported ? { passive: true } : false,
-);
-```
-
-Here we're adding a listener for the {{domxref("Element/mouseup_event", "mouseup")}}
-event on the element `someElement`. For the third parameter, if
-`passiveSupported` is `true`, we're specifying an
-`options` object with `passive` set to
-`true`; otherwise, we know that we need to pass a Boolean, and we pass
-`false` as the value of the `useCapture` parameter.
-
-You can learn more in the [Implementing feature detection](/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/Feature_detection) documentation and the explainer about
-[`EventListenerOptions`](https://github.com/WICG/EventListenerOptions/blob/gh-pages/explainer.md#feature-detection)
-from the [Web Incubator Community Group](https://wicg.github.io/admin/charter.html).
-
 ### The value of "this" within the handler
 
 It is often desirable to reference the element on which the event handler was fired,
@@ -426,12 +352,6 @@ Since it can't be canceled, event listeners can't block page rendering anyway.
 
 See [Improving scroll performance using passive listeners](#improving_scroll_performance_using_passive_listeners) for an example showing the effect of passive listeners.
 
-### Older browsers
-
-In older browsers that don't support the `options` parameter to
-`addEventListener()`, attempting to use it prevents the use of the
-`useCapture` argument without proper use of [feature detection](#safely_detecting_option_support).
-
 ## Examples
 
 ### Add a simple listener
@@ -754,10 +674,6 @@ Click the outer, middle, inner containers respectively to see how the options wo
 
 {{ EmbedLiveSample('Example_of_options_usage', 600, 630) }}
 
-Before using a particular value in the `options` object, it's a
-good idea to ensure that the user's browser supports it, since these are an addition
-that not all browsers have supported historically. See [Safely detecting option support](#safely_detecting_option_support) for details.
-
 ### Event listener with multiple options
 
 You can set more than one of the options in the `options` parameter. In the following example we are setting two options: