typeof

switch(expression) {
	case x:
		// code block
		break;
	case y:
		// code block
		break;
	default:
		break;
};

document.getElementById("conLogin").style.display="none"; //none|block

for (let i = 0; i < 5; i++) {
	text += "The number is " + i + "<br>";
};

//JSON
<p id="nodata"></p>
<p id="adadata"></p>
<p id="isidata"></p>
<script>
const nodatatxt = '{"success":0}';
const objnodata = JSON.parse(nodatatxt);
document.getElementById("nodata").innerHTML = objnodata.success ;

const adadatatxt = '{"success":1,'+
'"data":['+
'{"rID":"1","sUserID":"a"},'+
'{"rID":"2","sUserID":"b"},'+
'{"rID":"3","sUserID":"c"}'+
']}';
const objadadata = JSON.parse(adadatatxt);
isisukses = objadadata.success;
ada = objadadata.data.length;
document.getElementById("adadata").innerHTML = ada;

text = "";
for (let i = 0; i < ada; i++) {
	text += "rID=" + objadadata.data[i]["rID"] + " sUserID=" + objadadata.data[i]["sUserID"] +"<br>";
};

document.getElementById("isidata").innerHTML = text;

</script>
//JSON

//add click when apps run
for (let i = 0; i < datanyaada; i++) {
	enidnya = "en"+resdata.data[i]["rID"];
	document.getElementById(enidnya).addEventListener("click", EditNama);
	gbidnya = "gb"+resdata.data[i]["rID"];
	document.getElementById(gbidnya).addEventListener("click", EditGbr);
	deidnya = "de"+resdata.data[i]["rID"];
	document.getElementById(deidnya).addEventListener("click", Delete);
};
//add click when apps run

//img uri
gbrnya = "data:image/jpg;base64,"+resdata.data[i]["imageData"];
imgnya = "<img width=100 height=75 src="+gbrnya+" >";
//img uri

//add del tr table out template in html.txt
function fAddRow() {
  var table = document.getElementById("t1");
	var x = document.getElementById("t1").rows.length; 
	var no = x-1;
  var row = table.insertRow(x-1);
  var cell0 = row.insertCell(0);
  var cell1 = row.insertCell(1);
  var cell2 = row.insertCell(2);
  var cell3 = row.insertCell(3);
  var cell4 = row.insertCell(4);
  cell0.innerHTML = "<td>"+no+"</td>";
  cell1.innerHTML = "<td>"+no+",a</td>";
  cell2.innerHTML = "<td>"+no+",b</td>";
  cell3.innerHTML = "<td><button name=\"bAdd\" onClick=\"fAddRow();\">Add</button></td>";
  cell4.innerHTML = "<td><button name=\"bDelete\" onClick=\"fDeleteRow("+no+");\">Delete</button></td>";

}

function fDeleteRow(y) {
  document.getElementById("t1").deleteRow(y);
	//alert(document.getElementById("t1").rows[y].cells[0].innerHTML); 
	//betulin no betulin bDelete 
	var z = document.getElementById("t1").rows.length; 	
	var y = z-1;

	for (let i = 1; i < y; i++) {
		document.getElementById("t1").rows[i].cells[0].innerHTML="<td>"+i+"</td>";
		document.getElementById("t1").rows[i].cells[1].innerHTML= "<td>"+i+",a</td>";
		document.getElementById("t1").rows[i].cells[2].innerHTML= "<td>"+i+",b</td>";
		document.getElementById("t1").rows[i].cells[4].innerHTML="<td><button name=\"bDelete\" onClick=\"fDeleteRow("+i+");\">Delete</button></td>";
	};

}	
//add del tr
element.disabled=true;

// set select option
const $select = document.querySelector('#mySelect');
$select.value = 'steve'


alert(calcCrow(59.3293371,13.4877472,59.3225525,13.4619422).toFixed(1));

//This function takes in latitude and longitude of two location and returns the distance between them as the crow flies (in km)
function calcCrow(lat1, lon1, lat2, lon2) {
  var R = 6371; // km
  var dLat = toRad(lat2-lat1);
  var dLon = toRad(lon2-lon1);
  var lat1 = toRad(lat1);
  var lat2 = toRad(lat2);

  var a = Math.sin(dLat/2) * Math.sin(dLat/2) +Math.sin(dLon/2) * Math.sin(dLon/2) * Math.cos(lat1) * Math.cos(lat2); 
  var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); 
  var d = R * c;
  return d;
};

// Converts numeric degrees to radians
function toRad(Value) {
	return Value * Math.PI / 180;
};

let num = 5.56789;
let n = num.toFixed(2);

text="adfc ewg";
let result = text.substr(1, 4);

let myVar = setInterval(function, milliseconds);
clearInterval(myVar);

document.getElementById("sMsg").focus();

//Array
const a=[];
a.push(value);
a.pop(value);
a.toString();
a.length=0;

focus to <a> aone
function focustwo() {
	document.getElementById("aone").focus();
};
<a id="aone" href="#">aone</a><br>

//String function

//String to number
parseInt(myString)

//String replace
let text = "Visit Microsoft!";
let result = text.replace("Microsoft", "W3Schools");

//String split
text.split(" ")    // Split on spaces

//String match
input=document.getElementById("input");
inputval=input.value;
ada=inputval.match(/\n/g);
tamp.innerHTML=ada.length;

//Date function
const d=new Date();
let tahun=d.getFullYear();
let bln=d.getMonth();
let tgl=d.getDate();
let jam=d.getHours();
let menit=d.getMinutes();
let detik=d.getSeconds();

//orientation 
switch (screen.orientation.type) {
  case "landscape-primary":
    break;
  case "landscape-secondary":
    break;
  case "portrait-secondary":
    break;
  case "portrait-primary":
    break;
  default:
    break;
};