Detect the platform on javascript

amber/layouts/home.html.haml

@@ -10,6 +10,8 @@
     %link(rel="stylesheet" href="/assets/bootstrap.min.css")
     %link(rel="stylesheet" href="/assets/font-awesome/css/font-awesome.min.css")
     %link(rel="stylesheet" href="/assets/style.css")
+    %script(src="/assets/js/jquery.min.js")
+    %script(src="/assets/js/download.js")
     %link(rel="icon" href="/favicon.ico" type="image/x-icon")
     = html_head_base
   %body.home
@@ -30,7 +32,7 @@
                 .introtext
                   = render 'home/intro'
                 .download.text-left
-                  %a.btn.btn-large.btn-primary{:href => 'install'}
+                  %a.btn.btn-large.btn-primary.download{:href => 'install'}
                     %i.fa.fa-download.fa-2x
                     %span
                       = t :download_bitmask

pages/assets/js/download.js

+$(document).ready(function() {
+  $(".download").click(function(e) {
+    e.preventDefault();
+    download();
+  }); 
+});
+
+function download() {
+  var link = "install";
+  if (navigator.platform.indexOf("Linux") != -1) {
+    link = "https://dl.bitmask.net/client/linux/stable/Bitmask-linux64-latest.tar.gz";
+  }
+  if (navigator.platform.indexOf("Mac") != -1) {
+    link = "https://dl.bitmask.net/client/osx/stable/Bitmask-latest.pkg";
+  }
+  if (navigator.platform.indexOf("Android") != -1) {
+    link = "install/android";
+  }
+  //if (navigator.platform.indexOf("Win") != -1) {
+  //}
+  window.location = link;
+};