code-boxx/0-JS-APPOINTMENT.MD

## 0-JS-APPOINTMENT.MD

      
    Raw
  

              0-JS-APPOINTMENT.MD
            
          
    JAVASCRIPT APPOINTMENT PWA

https://code-boxx.com/javascript-appointment-scheduler/
NOTES


Access https://your-site.com/1-js-appo.html in your browser.
Not newbie-friendly, but it's a good study for progressive web apps.

IMAGES


LICENSE

Copyright by Code Boxx
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

  
## 1-js-appo.html
<!DOCTYPE html>
<html>
  <head>
    <!-- TITLE + CHARSET + DESCRIPTION + VIEWPORT + FAVICON -->
    <title>JS Appointment Scheduler</title>
    <meta charset="utf-8">
    <meta name="description" content="Appointment Scheduler">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.5">
    <link rel="icon" href="favicon.png" type="image/png">

    <!-- ANDROID + CHROME + APPLE + WINDOWS APP -->
    <meta name="mobile-web-app-capable" content="yes">
    <meta name="theme-color" content="white">
    <link rel="apple-touch-icon" href="icon-512.png">
    <meta name="apple-mobile-web-app-capable" content="yes">
    <meta name="apple-mobile-web-app-status-bar-style" content="black">
    <meta name="apple-mobile-web-app-title" content="Scheduler">
    <meta name="msapplication-TileImage" content="icon-512.png">
    <meta name="msapplication-TileColor" content="#ffffff">

    <!-- WEB APP MANIFEST -->
    <!-- https://web.dev/add-manifest/ -->
    <link rel="manifest" href="3a-manifest.json">

    <!-- SERVICE WORKER -->
    <script>
    if ("serviceWorker" in navigator) {
      navigator.serviceWorker.register("3b-worker.js");
    }
    </script>

    <!-- STYLESHEET + JAVASCRIPT -->
    <link href="https://fonts.googleapis.com/icon?family=Material+Icons" rel="stylesheet">
    <script src="2-js-appo.js"></script>
    <link rel="stylesheet" href="2-js-appo.css">
  </head>
  <body>
    <!-- (A) APPOINTMENTS -->
    <div id="appoWrap">
      <!-- (A1) HEADER -->
      <div id="appoHead">
        <div id="appoLast" class="mi" onclick="appo.cycle(false)">
          arrow_back_ios
        </div>
        <div id="appoNow"></div>
        <div id="appoAdd" class="mi" onclick="appo.toggle(true)">
          add
        </div>
        <div id="appoNext" class="mi" onclick="appo.cycle(true)">
          arrow_forward_ios
        </div>
      </div>

      <!-- (A2) APPOINTMENTS LIST -->
      <div id="appoList"></div>
    </div>

    <!-- (B) APPOINTMENT EVENT FORM -->
    <div id="appoFormWrap"><form id="appoForm" onsubmit="return appo.save()">
      <div id="formClose" class="mi" onclick="appo.toggle(false)">
        close
      </div>
      <input type="hidden" id="formID">
      <label>From</label>
      <input type="datetime-local" id="formFrom" required>
      <label>To</label>
      <input type="datetime-local" id="formTo" required>
      <label>Details</label>
      <input type="text" id="formTxt" required>
      <label>Text Color</label>
      <input type="color" id="formTC" required value="#ffffff">
      <label>Background Color</label>
      <input type="color" id="formBC" required value="#000000">
      <input type="submit" value="Save">
    </form></div>
  </body>
</html>

## 2-js-appo.css
/* (A) WHOLE PAGE */
.mi{font-family:"Material Icons";font-weight:400;font-style:normal;text-decoration:none;letter-spacing:normal;text-transform:none;display:inline-block;white-space:nowrap;word-wrap:normal;direction:ltr;-webkit-font-feature-settings:"liga";-webkit-font-smoothing:antialiased}
* {
  font-family: Arial, Helvetica, sans-serif;
  box-sizing: border-box;
}
body {
  padding: 0;
  margin: 0;
  background: #f2f2f2;
}
#appoLast, #appoNext, #appoAdd, #appoList .row .del, #appoList .row .txt { cursor: pointer; }

/* (B) APPOINTMENTS WRAPPER */
#appoWrap {
  max-width: 1000px;
  padding: 15px;
  margin: 0 auto;
}

/* (C) APPOINTMENTS HEADER */
#appoHead {
  display: flex;
  font-size: 20px;
  color: #fff;
  background: #0a3687;
}
#appoLast, #appoNext, #appoAdd, #appoNow { padding: 15px; }
#appoNow {
  flex-grow: 1;
  text-align: center;
}

/* (D) APPOINTMENTS LIST */
#appoList {
  display: grid;
  width: 100%;
  overflow: auto;
}
#appoList .cell, #appoList .row .del, #appoList .row .txt { padding: 10px; }
#appoList .head {
  font-weight: 700;
  color: #fff;
  background: #204a97;
}
#appoList .row { display: flex; }
#appoList .row .del {
  color: #fff;
  background: #972020;
}
#appoList .row .txt { flex-grow: 1; }

/* (E) APPOINTMENT FORM WRAPPER */
#appoFormWrap {
  /* (E1) FULL PAGE */
  position: fixed;
  top: 0; left: 0; z-index: 99;
  width: 100vw; height: 100vh;

  /* (E2) CENTERED */
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.5);

  /* (E3) HIDDEN */
  visibility: hidden; opacity: 0;
  transition: opacity 0.3s;
}
#appoFormWrap.show { visibility: visible; opacity: 1; }

/* (F) APPOINTMENT FORM */
#appoForm {
  position: relative;
  width: 380px;
  padding: 20px;
  background: #fff;
}
#formClose {
  position: absolute;
  top: 0; right: 0;
  padding: 10px;
  color: #fff;
  background: #972020;
  cursor: pointer;
}
#appoForm label, #appoForm input {
  display: block;
  width: 100%;
}
#appoForm input { padding: 10px; }
#appoForm label { padding: 10px 0; }
#appoForm input[type=color] {
  border: 0;
  padding: 0;
  background: 0;
  height: 30px;
}
#appoForm input[type=submit] {
  margin-top: 20px;
  padding: 15px 0;
  border: 0;
  color: #fff;
  background: #0a3687;
  cursor: pointer;
}

## 2-js-appo.js
var appo = {
  // (A) PROPERTIES
  // (A1) INDEXED DB
  iName : "jsAppo", // idb name
  iDB : null, iTX : null, // idb objects

  // (A2) HTML ELEMENTS
  hNow : null, // html current year month
  hList : null, // html appointment list
  hForm : null, // html appointment form
  fID : null, fFrom : null, fTo : null, // html form
  fTxt : null, fTC : null, fBC : null, // html form

  // (A3) PERIOD
  month : null, // current month
  year : null, // current year
  days : null, // days in month for current month/year

  // (B) INIT
  init : () => {
    // (B1) IDB SUPPORT CHECK
    window.indexedDB = window.indexedDB || window.mozIndexedDB || window.webkitIndexedDB || window.msIndexedDB;
    if (!window.indexedDB) {
      alert("Your browser does not support indexed database.");
      return;
    }

    // (B2) OPEN "MYLIB" DATABASE
    let req = window.indexedDB.open(appo.iName, 1);

    // (B3) ON DATABASE ERROR
    req.onerror = evt => {
      alert("Indexed DB init error - " + evt.message);
      console.error(evt);
    };

    // (B4) UPGRADE NEEDED
    req.onupgradeneeded = evt => {
      // (B4-1) INIT UPGRADE
      appo.iDB = evt.target.result;
      appo.iDB.onerror = evt => {
        alert("Indexed DB upgrade error - " + evt.message);
        console.error(evt);
      };

      // (B4-2) VERSION 1
      if (evt.oldVersion < 1) {
        let store = appo.iDB.createObjectStore(appo.iName, {
          keyPath: "id",
          autoIncrement: true
        });
        store.createIndex("from", "from");
        store.createIndex("to", "to");
      }
    };

    // (B5) OPEN DATABASE OK
    req.onsuccess = evt => {
      // (B5-1) REGISTER IDB OBJECTS
      appo.iDB = evt.target.result;
      appo.iTX = () => {
        return appo.iDB
        .transaction(appo.iName, "readwrite")
        .objectStore(appo.iName);
      };

      // (B5-2) GET HTML ELEMENTS
      appo.hNow = document.getElementById("appoNow");
      appo.hList = document.getElementById("appoList");
      appo.hForm = document.getElementById("appoFormWrap");
      appo.fID = document.getElementById("formID");
      appo.fFrom = document.getElementById("formFrom");
      appo.fTo = document.getElementById("formTo");
      appo.fTxt = document.getElementById("formTxt");
      appo.fTC = document.getElementById("formTC");
      appo.fBC = document.getElementById("formBC");

      // (B5-3) CURRENT DATE
      let today = new Date();
      appo.month = today.getMonth() + 1; // jan is 0!
      appo.year = today.getFullYear();

      // (B5-4) DRAW APPOINTMENTS
      appo.draw();
    };
  },

  // (C) HELPER FUNCTION - DATE TO UNIX TIMESTAMP
  dtu : date => Math.floor((+new Date(date)) / 1000),

  // (D) HELPER FUNCTION - UNIX TIMESTAMP TO DATE
  utd : unix => new Date(unix*1000).toISOString().substring(0,16),

  // (E) DRAW APPOINTMENTS FOR SELECTED MONTH
  draw : () => {
    // (E1) CURRENT MONTH YEAR
    let months = ["", "Jan", "Feb", "Mar", "Apr", "May", "Jun",
                  "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];
    appo.hNow.innerHTML = `${months[appo.month]} ${appo.year}`;
    delete months;

    // (E2) FIRST ROW - DAYS IN MONTH
    let cell;
    appo.days = new Date(appo.year, appo.month, 0).getDate();
    appo.hList.style.gridTemplateColumns = `repeat(${appo.days}, 100px)`;
    appo.hList.innerHTML = "";
    for (let d=1; d<=appo.days; d++) {
      cell = document.createElement("div");
      cell.className = "cell head";
      cell.innerHTML = d;
      appo.hList.append(cell);
    }

    // (E3) FOLLOWING ROWS - APPOINTMENT EVENTS
    // (E3-1) FLAGS & VARS
    let first = appo.dtu(`${appo.year}-${appo.month<10?"0"+appo.month:appo.month}-01T00:00`),
        last  = appo.dtu(`${appo.year}-${appo.month<10?"0"+appo.month:appo.month}-${appo.days}T00:00`),
        idx = null, more = true, drawn = {}, row = 2;

    // (E3-2) HELPER FUNCTION - DRAW APPOINTMENT EVENT
    let rower = evt => {
      const cursor = evt.target.result;
      if (cursor) {
        if (drawn[cursor.value.id]==undefined) {
          let cx = cursor.value.from < first ? 1 : new Date(cursor.value.from * 1000).getDate(),
              cy = cursor.value.to > last ? appo.days + 1 : new Date(cursor.value.to * 1000).getDate() + 1;

          cell = document.createElement("div");
          cell.className = "row";
          cell.style.gridRow = row;
          cell.style.gridColumn = `${cx}/${cy}`;
          cell.style.color = cursor.value.tc;
          cell.style.background = cursor.value.bc;
          cell.innerHTML = `<div class="mi del" onclick="appo.del(${cursor.value.id});">clear</div>
          <div class="txt" onclick="appo.toggle(${cursor.value.id});">${cursor.value.txt}</div>`;
          appo.hList.append(cell);
          drawn[cursor.value.id] = 1; row++;
        }
        cursor.continue();
      } else { if (more) {
        more = false;
        idx = appo.iTX().index("to").openCursor(range = IDBKeyRange.bound(first, last));
        idx.onsuccess = rower;
      }}
    };

    // (E3-3) GET & DRAW ENTRIES
    idx = appo.iTX().index("from").openCursor(range = IDBKeyRange.bound(first, last));
    idx.onsuccess = rower;
  },

  // (F) CYCLE MONTH
  cycle : next => {
    if (next) { appo.month++; } else { appo.month--; }
    if (appo.month==13) { appo.month = 1; appo.year++; }
    if (appo.month==0) { appo.month = 12; appo.year--; }
    appo.draw();
  },

  // (G) TOGGLE APPOINTMENT FORM
  toggle : id => {
    // (G1) HIDE
    if (id == false) {
      appo.hForm.classList.remove("show");
      appo.fID.value = "";
      appo.fFrom.value = "";
      appo.fTo.value = "";
      appo.fTxt.value = "";
      appo.fTC.value = "#ffffff";
      appo.fBC.value = "#000000";
    }

    // (G2) SHOW
    else {
      if (Number.isInteger(id)) {
        let req = appo.iTX().get(id);
        req.onsuccess = evt => {
          appo.fID.value = req.result.id;
          appo.fFrom.value = appo.utd(req.result.from);
          appo.fTo.value = appo.utd(req.result.to);
          appo.fTxt.value = req.result.txt;
          appo.fTC.value = req.result.tc;
          appo.fBC.value = req.result.bc;
        };
      }
      appo.hForm.classList.add("show");
    }
  },

  // (H) SAVE APPOINTMENT EVENT
  save : () => {
    // (H1) FORM DATA
    let data = {
      id : appo.fID.value,
      from : appo.dtu(appo.fFrom.value),
      to : appo.dtu(appo.fTo.value),
      txt : appo.fTxt.value,
      tc : appo.fTC.value,
      bc : appo.fBC.value
    };

    // (H2) DATE/TIME CHECK
    if (data.to < data.from) {
      alert("'Date From' cannot be later than 'Date To'");
      return false;
    }

    // (H3) SAVE EVENT
    if (data.id == "") { delete data.id; }
    else { data.id = parseInt(data.id); }
    appo.iTX().put(data);

    // (H4) UPDATE HTML INTERFACE
    appo.toggle(false);
    appo.draw();
    return false;
  },

  // (I) DELETE APPOINTMENT EVENT
  del : id => { if (confirm("Delete event?")) {
    appo.iTX().delete(id);
    appo.draw();
  }}
};
window.onload = appo.init;

## 3a-manifest.json
{
  "short_name": "Scheduler",
  "name": "Appointment Scheduler",
  "icons": [{
    "src": "favicon.png",
    "sizes": "64x64",
    "type": "image/png"
  }, {
    "src": "icon-512.png",
    "sizes": "512x512",
    "type": "image/png"
  }],
  "start_url": "1-js-appo.html",
  "scope": "/",
  "background_color": "white",
  "theme_color": "white",
  "display": "standalone"
}

## 3b-worker.js
// (A) CREATE/INSTALL CACHE
self.addEventListener("install", evt => {
  self.skipWaiting();
  evt.waitUntil(
    caches.open("JSAppo")
    .then(cache => cache.addAll([
      "favicon.png",
      "icon-512.png",
      "maticon.woff2",
      "1-js-appo.html",
      "2-js-appo.js",
      "2-js-appo.css"
    ]))
    .catch(err => console.error(err))
  );
});

// (B) CLAIM CONTROL INSTANTLY
self.addEventListener("activate", evt => self.clients.claim());

// (C) LOAD FROM CACHE FIRST, FALLBACK TO NETWORK IF NOT FOUND
self.addEventListener("fetch", evt => evt.respondWith(
  caches.match(evt.request).then(res => res || fetch(evt.request))
));
	<!DOCTYPE html>
	<html>
	<head>
	<!-- TITLE + CHARSET + DESCRIPTION + VIEWPORT + FAVICON -->
	<title>JS Appointment Scheduler</title>
	<meta charset="utf-8">
	<meta name="description" content="Appointment Scheduler">
	<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.5">
	<link rel="icon" href="favicon.png" type="image/png">

	<!-- ANDROID + CHROME + APPLE + WINDOWS APP -->
	<meta name="mobile-web-app-capable" content="yes">
	<meta name="theme-color" content="white">
	<link rel="apple-touch-icon" href="icon-512.png">
	<meta name="apple-mobile-web-app-capable" content="yes">
	<meta name="apple-mobile-web-app-status-bar-style" content="black">
	<meta name="apple-mobile-web-app-title" content="Scheduler">
	<meta name="msapplication-TileImage" content="icon-512.png">
	<meta name="msapplication-TileColor" content="#ffffff">

	<!-- WEB APP MANIFEST -->
	<!-- https://web.dev/add-manifest/ -->
	<link rel="manifest" href="3a-manifest.json">

	<!-- SERVICE WORKER -->
	<script>
	if ("serviceWorker" in navigator) {
	navigator.serviceWorker.register("3b-worker.js");
	}
	</script>

	<!-- STYLESHEET + JAVASCRIPT -->
	<link href="https://fonts.googleapis.com/icon?family=Material+Icons" rel="stylesheet">
	<script src="2-js-appo.js"></script>
	<link rel="stylesheet" href="2-js-appo.css">
	</head>
	<body>
	<!-- (A) APPOINTMENTS -->
	<div id="appoWrap">
	<!-- (A1) HEADER -->
	<div id="appoHead">
	<div id="appoLast" class="mi" onclick="appo.cycle(false)">
	arrow_back_ios
	</div>
	<div id="appoNow"></div>
	<div id="appoAdd" class="mi" onclick="appo.toggle(true)">
	add
	</div>
	<div id="appoNext" class="mi" onclick="appo.cycle(true)">
	arrow_forward_ios
	</div>
	</div>

	<!-- (A2) APPOINTMENTS LIST -->
	<div id="appoList"></div>
	</div>

	<!-- (B) APPOINTMENT EVENT FORM -->
	<div id="appoFormWrap"><form id="appoForm" onsubmit="return appo.save()">
	<div id="formClose" class="mi" onclick="appo.toggle(false)">
	close
	</div>
	<input type="hidden" id="formID">
	<label>From</label>
	<input type="datetime-local" id="formFrom" required>
	<label>To</label>
	<input type="datetime-local" id="formTo" required>
	<label>Details</label>
	<input type="text" id="formTxt" required>
	<label>Text Color</label>
	<input type="color" id="formTC" required value="#ffffff">
	<label>Background Color</label>
	<input type="color" id="formBC" required value="#000000">
	<input type="submit" value="Save">
	</form></div>
	</body>
	</html>
	/* (A) WHOLE PAGE */
	.mi{font-family:"Material Icons";font-weight:400;font-style:normal;text-decoration:none;letter-spacing:normal;text-transform:none;display:inline-block;white-space:nowrap;word-wrap:normal;direction:ltr;-webkit-font-feature-settings:"liga";-webkit-font-smoothing:antialiased}
	* {
	font-family: Arial, Helvetica, sans-serif;
	box-sizing: border-box;
	}
	body {
	padding: 0;
	margin: 0;
	background: #f2f2f2;
	}
	#appoLast, #appoNext, #appoAdd, #appoList .row .del, #appoList .row .txt { cursor: pointer; }

	/* (B) APPOINTMENTS WRAPPER */
	#appoWrap {
	max-width: 1000px;
	padding: 15px;
	margin: 0 auto;
	}

	/* (C) APPOINTMENTS HEADER */
	#appoHead {
	display: flex;
	font-size: 20px;
	color: #fff;
	background: #0a3687;
	}
	#appoLast, #appoNext, #appoAdd, #appoNow { padding: 15px; }
	#appoNow {
	flex-grow: 1;
	text-align: center;
	}

	/* (D) APPOINTMENTS LIST */
	#appoList {
	display: grid;
	width: 100%;
	overflow: auto;
	}
	#appoList .cell, #appoList .row .del, #appoList .row .txt { padding: 10px; }
	#appoList .head {
	font-weight: 700;
	color: #fff;
	background: #204a97;
	}
	#appoList .row { display: flex; }
	#appoList .row .del {
	color: #fff;
	background: #972020;
	}
	#appoList .row .txt { flex-grow: 1; }

	/* (E) APPOINTMENT FORM WRAPPER */
	#appoFormWrap {
	/* (E1) FULL PAGE */
	position: fixed;
	top: 0; left: 0; z-index: 99;
	width: 100vw; height: 100vh;

	/* (E2) CENTERED */
	display: flex;
	align-items: center;
	justify-content: center;
	background: rgba(0, 0, 0, 0.5);

	/* (E3) HIDDEN */
	visibility: hidden; opacity: 0;
	transition: opacity 0.3s;
	}
	#appoFormWrap.show { visibility: visible; opacity: 1; }

	/* (F) APPOINTMENT FORM */
	#appoForm {
	position: relative;
	width: 380px;
	padding: 20px;
	background: #fff;
	}
	#formClose {
	position: absolute;
	top: 0; right: 0;
	padding: 10px;
	color: #fff;
	background: #972020;
	cursor: pointer;
	}
	#appoForm label, #appoForm input {
	display: block;
	width: 100%;
	}
	#appoForm input { padding: 10px; }
	#appoForm label { padding: 10px 0; }
	#appoForm input[type=color] {
	border: 0;
	padding: 0;
	background: 0;
	height: 30px;
	}
	#appoForm input[type=submit] {
	margin-top: 20px;
	padding: 15px 0;
	border: 0;
	color: #fff;
	background: #0a3687;
	cursor: pointer;
	}
	var appo = {
	// (A) PROPERTIES
	// (A1) INDEXED DB
	iName : "jsAppo", // idb name
	iDB : null, iTX : null, // idb objects

	// (A2) HTML ELEMENTS
	hNow : null, // html current year month
	hList : null, // html appointment list
	hForm : null, // html appointment form
	fID : null, fFrom : null, fTo : null, // html form
	fTxt : null, fTC : null, fBC : null, // html form

	// (A3) PERIOD
	month : null, // current month
	year : null, // current year
	days : null, // days in month for current month/year

	// (B) INIT
	init : () => {
	// (B1) IDB SUPPORT CHECK
	window.indexedDB = window.indexedDB \|\| window.mozIndexedDB \|\| window.webkitIndexedDB \|\| window.msIndexedDB;
	if (!window.indexedDB) {
	alert("Your browser does not support indexed database.");
	return;
	}

	// (B2) OPEN "MYLIB" DATABASE
	let req = window.indexedDB.open(appo.iName, 1);

	// (B3) ON DATABASE ERROR
	req.onerror = evt => {
	alert("Indexed DB init error - " + evt.message);
	console.error(evt);
	};

	// (B4) UPGRADE NEEDED
	req.onupgradeneeded = evt => {
	// (B4-1) INIT UPGRADE
	appo.iDB = evt.target.result;
	appo.iDB.onerror = evt => {
	alert("Indexed DB upgrade error - " + evt.message);
	console.error(evt);
	};

	// (B4-2) VERSION 1
	if (evt.oldVersion < 1) {
	let store = appo.iDB.createObjectStore(appo.iName, {
	keyPath: "id",
	autoIncrement: true
	});
	store.createIndex("from", "from");
	store.createIndex("to", "to");
	}
	};

	// (B5) OPEN DATABASE OK
	req.onsuccess = evt => {
	// (B5-1) REGISTER IDB OBJECTS
	appo.iDB = evt.target.result;
	appo.iTX = () => {
	return appo.iDB
	.transaction(appo.iName, "readwrite")
	.objectStore(appo.iName);
	};

	// (B5-2) GET HTML ELEMENTS
	appo.hNow = document.getElementById("appoNow");
	appo.hList = document.getElementById("appoList");
	appo.hForm = document.getElementById("appoFormWrap");
	appo.fID = document.getElementById("formID");
	appo.fFrom = document.getElementById("formFrom");
	appo.fTo = document.getElementById("formTo");
	appo.fTxt = document.getElementById("formTxt");
	appo.fTC = document.getElementById("formTC");
	appo.fBC = document.getElementById("formBC");

	// (B5-3) CURRENT DATE
	let today = new Date();
	appo.month = today.getMonth() + 1; // jan is 0!
	appo.year = today.getFullYear();

	// (B5-4) DRAW APPOINTMENTS
	appo.draw();
	};
	},

	// (C) HELPER FUNCTION - DATE TO UNIX TIMESTAMP
	dtu : date => Math.floor((+new Date(date)) / 1000),

	// (D) HELPER FUNCTION - UNIX TIMESTAMP TO DATE
	utd : unix => new Date(unix*1000).toISOString().substring(0,16),

	// (E) DRAW APPOINTMENTS FOR SELECTED MONTH
	draw : () => {
	// (E1) CURRENT MONTH YEAR
	let months = ["", "Jan", "Feb", "Mar", "Apr", "May", "Jun",
	"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];
	appo.hNow.innerHTML = `${months[appo.month]} ${appo.year}`;
	delete months;

	// (E2) FIRST ROW - DAYS IN MONTH
	let cell;
	appo.days = new Date(appo.year, appo.month, 0).getDate();
	appo.hList.style.gridTemplateColumns = `repeat(${appo.days}, 100px)`;
	appo.hList.innerHTML = "";
	for (let d=1; d<=appo.days; d++) {
	cell = document.createElement("div");
	cell.className = "cell head";
	cell.innerHTML = d;
	appo.hList.append(cell);
	}

	// (E3) FOLLOWING ROWS - APPOINTMENT EVENTS
	// (E3-1) FLAGS & VARS
	let first = appo.dtu(`${appo.year}-${appo.month<10?"0"+appo.month:appo.month}-01T00:00`),
	last = appo.dtu(`${appo.year}-${appo.month<10?"0"+appo.month:appo.month}-${appo.days}T00:00`),
	idx = null, more = true, drawn = {}, row = 2;

	// (E3-2) HELPER FUNCTION - DRAW APPOINTMENT EVENT
	let rower = evt => {
	const cursor = evt.target.result;
	if (cursor) {
	if (drawn[cursor.value.id]==undefined) {
	let cx = cursor.value.from < first ? 1 : new Date(cursor.value.from * 1000).getDate(),
	cy = cursor.value.to > last ? appo.days + 1 : new Date(cursor.value.to * 1000).getDate() + 1;

	cell = document.createElement("div");
	cell.className = "row";
	cell.style.gridRow = row;
	cell.style.gridColumn = `${cx}/${cy}`;
	cell.style.color = cursor.value.tc;
	cell.style.background = cursor.value.bc;
	cell.innerHTML = `<div class="mi del" onclick="appo.del(${cursor.value.id});">clear</div>
	<div class="txt" onclick="appo.toggle(${cursor.value.id});">${cursor.value.txt}</div>`;
	appo.hList.append(cell);
	drawn[cursor.value.id] = 1; row++;
	}
	cursor.continue();
	} else { if (more) {
	more = false;
	idx = appo.iTX().index("to").openCursor(range = IDBKeyRange.bound(first, last));
	idx.onsuccess = rower;
	}}
	};

	// (E3-3) GET & DRAW ENTRIES
	idx = appo.iTX().index("from").openCursor(range = IDBKeyRange.bound(first, last));
	idx.onsuccess = rower;
	},

	// (F) CYCLE MONTH
	cycle : next => {
	if (next) { appo.month++; } else { appo.month--; }
	if (appo.month==13) { appo.month = 1; appo.year++; }
	if (appo.month==0) { appo.month = 12; appo.year--; }
	appo.draw();
	},

	// (G) TOGGLE APPOINTMENT FORM
	toggle : id => {
	// (G1) HIDE
	if (id == false) {
	appo.hForm.classList.remove("show");
	appo.fID.value = "";
	appo.fFrom.value = "";
	appo.fTo.value = "";
	appo.fTxt.value = "";
	appo.fTC.value = "#ffffff";
	appo.fBC.value = "#000000";
	}

	// (G2) SHOW
	else {
	if (Number.isInteger(id)) {
	let req = appo.iTX().get(id);
	req.onsuccess = evt => {
	appo.fID.value = req.result.id;
	appo.fFrom.value = appo.utd(req.result.from);
	appo.fTo.value = appo.utd(req.result.to);
	appo.fTxt.value = req.result.txt;
	appo.fTC.value = req.result.tc;
	appo.fBC.value = req.result.bc;
	};
	}
	appo.hForm.classList.add("show");
	}
	},

	// (H) SAVE APPOINTMENT EVENT
	save : () => {
	// (H1) FORM DATA
	let data = {
	id : appo.fID.value,
	from : appo.dtu(appo.fFrom.value),
	to : appo.dtu(appo.fTo.value),
	txt : appo.fTxt.value,
	tc : appo.fTC.value,
	bc : appo.fBC.value
	};

	// (H2) DATE/TIME CHECK
	if (data.to < data.from) {
	alert("'Date From' cannot be later than 'Date To'");
	return false;
	}

	// (H3) SAVE EVENT
	if (data.id == "") { delete data.id; }
	else { data.id = parseInt(data.id); }
	appo.iTX().put(data);

	// (H4) UPDATE HTML INTERFACE
	appo.toggle(false);
	appo.draw();
	return false;
	},

	// (I) DELETE APPOINTMENT EVENT
	del : id => { if (confirm("Delete event?")) {
	appo.iTX().delete(id);
	appo.draw();
	}}
	};
	window.onload = appo.init;
	{
	"short_name": "Scheduler",
	"name": "Appointment Scheduler",
	"icons": [{
	"src": "favicon.png",
	"sizes": "64x64",
	"type": "image/png"
	}, {
	"src": "icon-512.png",
	"sizes": "512x512",
	"type": "image/png"
	}],
	"start_url": "1-js-appo.html",
	"scope": "/",
	"background_color": "white",
	"theme_color": "white",
	"display": "standalone"
	}
	// (A) CREATE/INSTALL CACHE
	self.addEventListener("install", evt => {
	self.skipWaiting();
	evt.waitUntil(
	caches.open("JSAppo")
	.then(cache => cache.addAll([
	"favicon.png",
	"icon-512.png",
	"maticon.woff2",
	"1-js-appo.html",
	"2-js-appo.js",
	"2-js-appo.css"
	]))
	.catch(err => console.error(err))
	);
	});

	// (B) CLAIM CONTROL INSTANTLY
	self.addEventListener("activate", evt => self.clients.claim());

	// (C) LOAD FROM CACHE FIRST, FALLBACK TO NETWORK IF NOT FOUND
	self.addEventListener("fetch", evt => evt.respondWith(
	caches.match(evt.request).then(res => res \|\| fetch(evt.request))
	));