Calculate Age in JavaScript

HTML:

<input type="date" id="DOB" name="DOB" />

 

 JAVASCRIPT in SCRIPT tags:

//Since new Date() created a date in the format mm/dd/yyyy, we need to format our dob to match the same format
var dob_formatted = switchMonthDate(document.getElementById(“DOB”).value);

//Calculate Age
//Subtract dob from today's date and divide by total milliseconds in a year
var age = Math.floor((new Date() - dob_formatted)/ 31536000000);


if(age >= 18)
{

console.log("adult");

}


function switchMonthDate(dateFirst)
{


if(dateFirst.indexOf("/") !== -1)
dateFirst=dateFirst.split("/");
else if(dateFirst.indexOf("-") !== -1)
dateFirst=dateFirst.split("-");
else if(dateFirst.indexOf(".") !== -1)
dateFirst=dateFirst.split(".");
var monthFirst=dateFirst[1]+"/"+dateFirst[0]+"/"+dateFirst[2];


return new Date(monthFirst);


}