[doc] Add language page for JavaScript/TypeScript

docs/_data/sidebars/pmd_sidebar.yml

@@ -409,6 +409,9 @@ entries:
     - title: Java
       url: /pmd_languages_java.html
       output: web, pdf
+    - title: JavaScript / TypeScript
+      url: /pmd_languages_js_ts.html
+      output: web, pdf
     - title: JSP
       url: /pmd_languages_jsp.html
       output: web, pdf

docs/pages/pmd/languages/js_ts.md

@@ -0,0 +1,16 @@
+---
+title: JavaScript and TypeScript
+permalink: pmd_languages_js_ts.html
+tags: [languages]
+summary: "JavaScript and TypeScript infos"
+---
+
+**JavaScript** support is using [Rhino](https://github.com/mozilla/rhino) for parsing and supports CPD as well as
+PMD with rules.
+
+See [Compatibility Table](https://mozilla.github.io/rhino/compat/engines.html) for supported language features.
+
+
+**TypeScript** is supported for Copy-Paste-Detection only and uses the ANTLR grammar from
+[antlr/grammars-v4](https://github.com/antlr/grammars-v4/tree/master/javascript/typescript).
+This grammar is published under the [MIT](https://opensource.org/licenses/MIT) license.