how to validate input type=date in javascript

var date_regex = /^(0[1-9]|1[0-2])\/(0[1-9]|1\d|2\d|3[01])\/(19|20)\d{2}$/;
if (!(date_regex.test(testDate))) {
    return false;
}function isValidDate(d){
    return !isNaN((new Date(d)).getTime());
}