docs: add docs for IE (#21824)

PR Close #21824

aio/README.md

@@ -105,8 +105,7 @@ The general setup is as follows:
 * Open a terminal, ensure the dependencies are installed; run an initial doc generation; then start the doc-viewer:
 
 ```bash
-yarn
-yarn docs
+yarn setup
 yarn start
 ```
 

aio/content/guide/browser-support.md

@@ -625,8 +625,13 @@ If you aren't using the CLI, you should add your polyfill scripts directly to th
     // __Zone_disable_requestAnimationFrame = true; // disable patch requestAnimationFrame
     // __Zone_disable_on_property = true; // disable patch onProperty such as onclick
     // __zone_symbol__BLACK_LISTED_EVENTS = ['scroll', 'mousemove']; // disable patch specified eventNames
-  </script>
 
+    /*
+     * in IE/Edge developer tools, the addEventListener will also be wrapped by zone.js
+     * with the following flag, it will bypass `zone.js` patch for IE/Edge
+     */
+    // __Zone_enable_cross_context_check = true;
+  </script>
   <!-- zone.js required by Angular -->
   <script src="node_modules/zone.js/dist/zone.js"></script>
 

aio/content/guide/setup.md

@@ -350,3 +350,10 @@ It's the perfect place to reproduce a bug when you want to
 <a href="https://github.com/angular/angular/issues/new" title="File an Angular issue">file an issue with Angular itself</a>.
 
 For real development, we strongly recommend [developing locally](guide/setup#develop-locally).
+
+## Appendix: develop locally with IE
+
+If you develop angular locally with `ng serve`, there will be `websocket` connection being setup automatically between browser and local dev server, so when your code change, browser can automatically refresh.
+
+In windows, by default one application can only have 6 websocket connections, <a href="https://msdn.microsoft.com/library/ee330736%28v=vs.85%29.aspx?f=255&MSPPError=-2147217396#websocket_maxconn" title="MSDN WebSocket settings">MSDN WebSocket Settings</a>.
+So if IE was refreshed manunally or automatically by `ng serve`, sometimes, the websocket will not close properly, when websocket connections exceed limitations, `SecurityError` will be thrown, this error will not affect the angular application, you can just restart IE to clear this error, or modify the windows registry to update the limitations.

aio/content/guide/typescript-configuration.md

@@ -135,3 +135,12 @@ QuickStart identifies two *typings*, or `d.ts`, files:
 you can view an example in the [webpack](guide/webpack) page.
 
 QuickStart doesn't require these typings but many of the samples do.
+
+
+{@a target}
+
+
+### *target*
+
+By default, the target is `es5`, you can configure the target to `es6` if you only want to deploy the application to
+es6 compatible browser. But if you configure the target to `es6` in some old browser such as `IE`, `Syntax Error` will be thrown.