Add Get The Time Zone Of The Client Computer as a javascript til

README.md

@@ -10,7 +10,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 For a steady stream of TILs from a variety of rocketeers, checkout
 [til.hashrocket.com](https://til.hashrocket.com/).
 
-_708 TILs and counting..._
+_709 TILs and counting..._
 
 ---
 
@@ -249,6 +249,7 @@ _708 TILs and counting..._
 - [Fill An Input With A Ton Of Text](javascript/fill-an-input-with-a-ton-of-text.md)
 - [Freeze An Object, Sorta](javascript/freeze-an-object-sorta.md)
 - [Get The Location And Size Of An Element](javascript/get-the-location-and-size-of-an-element.md)
+- [Get The Time Zone Of The Client Computer](javascript/get-the-time-zone-of-the-client-computer.md)
 - [Globally Install A Package With Yarn](javascript/globally-install-a-package-with-yarn.md)
 - [Immutable Remove With The Spread Operator](javascript/immutable-remove-with-the-spread-operator.md)
 - [Initialize A New JavaScript Project With Yarn](javascript/initialize-a-new-javascript-project-with-yarn.md)

javascript/get-the-time-zone-of-the-client-computer.md

@@ -0,0 +1,18 @@
+# Get The Time Zone Of The Client Computer
+
+The
+[`resolvedOptions`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DateTimeFormat/resolvedOptions)
+function on `Intl.DateTimeFormat.prototype` provides a number of pieces of
+information about the client computer. It includes information such as the
+locale and the numbering system. It also has the time zone for that machine.
+
+Try running this line of JavaScript in your own browser.
+
+```javascript
+$ Intl.DateTimeFormat().resolvedOptions().timeZone
+```
+
+When I run it, I get `America/Chicago`.
+
+You can use this within your client-side code as a way of determining in
+which time zone your users are.