javascript - Age Check and jquery

Question

Does anyone have any solid examples of how to implement a jQuery or javascript based age checker? I'm looking to send someone to a page where they need to enter in the Day, Month and Year at least once a day when they hit any page on the site. Once they validate as 18 then they would not be pestered again until the next day if they return.

Any ideas?

Answer 1

A cookie-based solution does seem a logical fit since you can programmatically modify them from JavaScript and you can set their expiry. Calculating the date in pure JavaScript can be done as such:

var millisPerYear = 1000 * 60 * 60 * 24 * 365;
var birthdate = new Date(year, month, day); // from user input.
var age = ((new Date().getTime()) - birthdate.getTime()) / millisPerYear;
// Now set the "age" cookie.

All that is left is for your server-side response handlers to return content conditionally based on the value of the "age" cookie from the request agent.