X-Git-Url: https://git.kengrimes.com/?p=kengrimes.com%2Ftheme.git;a=blobdiff_plain;f=static%2Fjs%2Fmain.js;h=069b2d46e8cb630fc8fb29ad610e10e57ab301ad;hp=fac5a3f78444eb7fe950e1c4030af128f41437b1;hb=0aab69a962e2a21071dbe5102f19c6712c513b00;hpb=af846c74fa32efa787846f3702e9f5a8050e7e51

diff --git a/static/js/main.js b/static/js/main.js
index fac5a3f..069b2d4 100644
--- a/static/js/main.js
+++ b/static/js/main.js
@@ -7,7 +7,9 @@
 */
 'use strict'
 window.onload = () => {
+  const header = document.body.getElementsByTagName('header').item(0)
   const nav = document.body.getElementsByTagName('nav').item(0)
+  const main = document.body.getElementsByTagName('main').item(0)
   const navAnchors = Array.from(nav.getElementsByTagName('div').item(0).getElementsByTagName('a'))
   const pageDisplay = nav.getElementsByTagName('footer').item(0)
   const currentPageName = `${pageDisplay.innerHTML}`
@@ -19,7 +21,34 @@ window.onload = () => {
     a.addEventListener('mouseout', () => pageDisplay.innerHTML = currentPageName)
   })
   updateNav()
+
+  let oldScrollY = window.scrollY
+  const _downDelay = 15
+  let downDelay = 0
+  const  _upDelay = 5
+  let upDelay = _upDelay
+  const navUp = () => nav.style.top = Math.min(parseInt(nav.style.top,10) + (oldScrollY - window.scrollY), 0) + 'px'
+  const navDown = () => nav.style.top = Math.max(parseInt(nav.style.top,10) - (window.scrollY - oldScrollY), -nav.offsetHeight) + 'px'
+  nav.style.top = 0 + 'px'
+  window.onscroll = () => {
+    if (window.matchMedia("(orientation: portrait)").matches) {
+      if (window.scrollY < oldScrollY) /* up */ {
+        if (upDelay-- <= 0)
+          downDelay = _downDelay
+        navUp()
+      }
+      else {
+        upDelay = _upDelay
+        if(downDelay-- <= 0)
+          navDown()
+        else
+          navUp()
+      }
+      oldScrollY = window.scrollY
+    }
+  }
 }
+  
 const resizeIFrame = (iframe) => {
   iframe.style.height = 0
   iframe.style.height = (iframe.contentWindow.document.body.scrollHeight * 1.2) + 'px';