Add cookie saving for day/night mode

js/docs.js

@@ -1,3 +1,37 @@
+// Cookie functions
+function createCookie(name,value,days) {
+    var expires = "";
+    if (days) {
+        var date = new Date();
+        date.setTime(date.getTime() + (days*24*60*60*1000));
+        expires = "; expires=" + date.toUTCString();
+    }
+    document.cookie = name + "=" + value + expires + "; path=/";
+}
+
+function readCookie(name) {
+    var nameEQ = name + "=";
+    var ca = document.cookie.split(';');
+    for(var i=0;i < ca.length;i++) {
+        var c = ca[i];
+        while (c.charAt(0)==' ') c = c.substring(1,c.length);
+        if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
+    }
+    return null;
+}
+
+function eraseCookie(name) {
+    createCookie(name,"",-1);
+}
+if (readCookie("night") == "true") {
+  document.getElementById('pagestyle').setAttribute('href', '/css/style-alt.css');
+  $('#switch-style').prop('checked', true);
+} else {
+  document.getElementById('pagestyle').setAttribute('href', '/css/style.css');
+  $('#switch-style').prop('checked', false);
+}
+
+
 /*
  *
  * swapStyleSheet*********************************************************************
@@ -97,11 +131,10 @@ $('#switch-style').change(function() {
 
     if ($(this).is(':checked')) {
         swapStyleSheet('/css/style-alt.css');
-
-
+        createCookie("night",true,999)
     } else {
         swapStyleSheet('/css/style.css');
-
+        eraseCookie("night")
     }
 });