<input type="date" name="input1" placeholder="YYYY-MM-DD" required pattern="[0-9]{4}-[0-9]{2}-[0-9]{2}" title="Enter a date in this formart YYYY-MM-DD"/>
<html>
<body>
date :
<span style="position: relative;display: inline-block;border: 1px solid #a9a9a9;height: 24px;width: 500px">
<input type="date" class="xDateContainer" onchange="setCorrect(this,'xTime');" style="position: absolute; opacity: 0.0;height: 100%;width: 100%;"><input type="text" id="xTime" name="xTime" value="dd / mm / yyyy" style="border: none;height: 90%;" tabindex="-1"><span style="display: inline-block;width: 20px;z-index: 2;float: right;padding-top: 3px;" tabindex="-1">▼</span>
</span>
<script language="javascript">
var matchEnterdDate=0;
//function to set back date opacity for non supported browsers
window.onload =function(){
var input = document.createElement('input');
input.setAttribute('type','date');
input.setAttribute('value', 'some text');
if(input.value === "some text"){
allDates = document.getElementsByClassName("xDateContainer");
matchEnterdDate=1;
for (var i = 0; i < allDates.length; i++) {
allDates[i].style.opacity = "1";
}
}
}
//function to convert enterd date to any format
function setCorrect(xObj,xTraget){
var date = new Date(xObj.value);
var month = date.getMonth();
var day = date.getDate();
var year = date.getFullYear();
if(month!='NaN'){
document.getElementById(xTraget).value=day+" / "+month+" / "+year;
}else{
if(matchEnterdDate==1){document.getElementById(xTraget).value=xObj.value;}
}
}
</script>
</body>
</html>
<div id="result"></div>
<p>Enter some text:
<input type="date" name="txt" id="datefield" onchange="dateval(value)"></p>
<button onclick="postdate()">submit</button>
<script>
var a;
// Set the *value* of the input element to
// yyyy-mm-dd (text is unchanged)
function dateval(val) {
var dv = document.getElementById("datefield");
a = val.split("-").reverse().join("-");
dv.type = "text";
dv.value = a;
}
// Extract the yyyy-mm-dd value from the inpuut element,
// format it to dd-mm-yyyy and put it in the div
function postdate() {
var dv = document.getElementById("datefield");
var z = a.split("-").reverse().join("-");
document.getElementById("result").innerHTML = a;
dv.type = "date";
dv.value = z;
}
</script>
let dateyear= "2020-03-18";
let arr = dateyear.split('-') //now we get array of these and we can made in any format as we want
let dateFormat = arr[2] + "-" + arr[1] + "-" + arr[0] //In dd-mm-yyyy format