<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8" name="viewport" content="width=device-width, initial-scale=1"/> <link rel="stylesheet" type="text/css" href="css/bootstrap.css"/> </head> <body> <nav class="navbar navbar-default"> <div class="contriner-fluid"> </div> </nav> <div class="col-md-6 well"> <hr style="border-top:1px dotted #ccc;"/> <div class="col-md-6"> <div class="form-inline"> <input type="date" id="birthday"/> </div> </div> </div> </body> </html>
function getAge() { var date = document.getElementById('birthday').value; if(date === ""){ alert("Please complete the required field!"); }else{ var today = new Date(); var birthday = new Date(date); var year = 0; if (today.getMonth() < birthday.getMonth()) { year = 1; } else if ((today.getMonth() == birthday.getMonth()) && today.getDate() < birthday.getDate()) { year = 1; } var age = today.getFullYear() - birthday.getFullYear() - year; if(age < 0){ age = 0; } document.getElementById('result').innerHTML = age; } }