diff --git a/html-js-css/README.md b/html-js-css/README.md
new file mode 100644
index 0000000..00c623b
--- /dev/null
+++ b/html-js-css/README.md
@@ -0,0 +1,52 @@
+# Quick Guide on HTML / Javascript / CSS
+
+* Quick Tutorial on HTML / Javascript / CSS
+* [W3.CSS](https://www.w3schools.com/w3css/default.asp)
+* [Javascript](https://www.w3schools.com/js/)
+* [HTML](https://www.w3schools.com/html/default.asp)
+* [Bootstrap CSS Framework](https://www.w3schools.com/bootstrap/bootstrap_ver.asp)
+* Tools
+ * Visual Studio Code
+ * Extension : Live Server
+
+## Javascript Library
+
+* [jQuery](https://www.w3schools.com/jquery/jquery_intro.asp)
+
+* syntax : `$(selector).action()`
+ * `$("p").hide()` : hide paragraph element
+ * `$("#test").hide()` : hide element with id=test
+ * `$(".test").hide()` : hide element with class=test
+ * `$(this).hide()` : hide current element
+ * [more...](https://www.w3schools.com/jquery/jquery_selectors.asp)
+
+* [download](https://jquery.com/download/) and add this
+
+ ```html
+
+
+
+
+ ```
+
+ ```html
+
+
+
+
+ ```
+
+* Events
+ * `.change()`
+ * `.click()`
+ * `.mouseenter()`
+ * [more...](https://www.w3schools.com/jquery/jquery_events.asp)
+
+* [AJAX](https://www.w3schools.com/jquery/jquery_ajax_intro.asp) (Asynchronous JavaScript and XML) : Exchange data with server
+
+ * `$("#div1").load("demo.txt")`
+ * `$.get(URL,data,callback)`
+ * `$.post(URL,data,callback)`
+
+* [References Overview](https://www.w3schools.com/jquery/jquery_ref_overview.asp)
+
diff --git a/mysql/README.md b/mysql/README.md
index bf9a5dd..df597bc 100644
--- a/mysql/README.md
+++ b/mysql/README.md
@@ -93,3 +93,36 @@ shell-js> util.loadDump("/mnt/data/worlddump", {dryRun: true})
shell-js> util.loadDump("razerpay-schema-prod-MY.sql", {threads: 88, waitDumpTimeout: 1800})
```
+## Performance Optimization
+
+* improve query for huge dataset
+
+* configuration `my-custom.cnf`
+
+```cnf
+[mysqld]
+innodb_buffer_pool_size = 2G
+```
+
+
+
+* configuration for `docker-compose.yml`
+
+```yml
+version: '3.1'
+
+services:
+
+ db:
+ image: mysql
+ command: --default-authentication-plugin=mysql_native_password
+ restart: always
+ ports:
+ - "3306:3306"
+ environment:
+ MYSQL_ROOT_PASSWORD: root
+ volumes:
+ - ./persistent_data:/var/lib/mysql
+ - ./etc/conf.d:/etc/mysql/conf.d
+```
+