How to validate age and alert if the current date is the user's birthday?

Question

Okay, I'm very new to Javascript (I started about 2 months ago in my computer's class) and I'm doing an assignment that requires a form that includes date of birth (with day/month/year each in a dropdown) and I need to be able to:

a) Confirm that the user is over 18 and send an alert if not.

and;

b) Provide a "happy birthday" message if the current day is the user's birthday

I've searched tirelessly for a solution but I can't find one that I understand. This is what I've got so far:

    <form name="contest">
    Date of Birth:
    Year: <select name="year">
            <option></option>
            <option>2015</option>
            <option>2014</option>
            <option>2013</option>
            <option>2012</option>
            <option>2011</option>
            <option>2010</option>
            <option>2009</option>
            <option>2008</option>
            <option>2007</option>
            <option>2006</option>
            <option>2005</option>
            <option>2004</option>
            <option>2003</option>
            <option>2002</option>
            <option>2001</option>
            <option>2000</option>
            <option>1999</option>
            <option>1998</option>
            <option>1997</option>
            <option>1996</option>
            <option>1995</option>
            <option>1994</option>
            <option>1993</option>
            <option>1992</option>
            <option>1991</option>
            <option>1990</option>
        </select>
    Month: <select name="month">
            <option></option>
            <option value="jan">January</option>
            <option value="feb">February</option>
            <option value="mar">March</option>
            <option value="apr">April</option>
            <option value="may">May</option>
            <option value="jun">June</option>
            <option value="jul">July</option>
            <option value="aug">August</option>
            <option value="sep">September</option>
            <option value="oct">October</option>
            <option value="nov">November</option>
            <option value="dec">December</option>
        </select>
    Day: <select name="day">
            <option></option>
            <option>01</option>
            <option>02</option>
            <option>03</option>
            <option>04</option>
            <option>05</option>
            <option>06</option>
            <option>07</option>
            <option>08</option>
            <option>09</option>
            <option>10</option>
            <option>11</option>
            <option>12</option>
            <option>13</option>
            <option>14</option>
            <option>15</option>
            <option>16</option>
            <option>17</option>
            <option>18</option>
            <option>19</option>
            <option>20</option>
            <option>21</option>
            <option>22</option>
            <option>23</option>
            <option>24</option>
            <option>25</option>
            <option>26</option>
            <option>27</option>
            <option>28</option>
            <option>29</option>
            <option>30</option>
            <option>31</option>
        </select>

    <input type="button" name="" onClick="checkInput(this.form)" value="Submit"/>
    <input type="reset"/>
</form>

Any help would be greatly appreciated! Thanks :)

Answer 1

Straightforward.

function checkInput()
{
  // get today's date.
  var today = new Date();
  today.setHours(0,0,0,0); // set time to start of day for comparison.

  // create a new date based on user input.
  var bdate = new Date(Date.parse( 
    document.querySelector('select[name="year"]').value + ' ' +
    document.querySelector('select[name="month"]').value + ' ' +
    document.querySelector('select[name="day"]').value
  ));
  today.setYear(0); // ignore year part of date.
  bdate.setYear(0); // ignore year part of date.

  if (today.valueOf() == bdate.valueOf())
  {
    alert('Happy Birthday');
  }
  else
  {
    alert('Merry Unbirthday.');
  }
}

Answer 2

In your function(checkInput) you need to check if the current date is equal with the date that the user has give. You can get current date via:

 var today = new Date(); var day = today.getDate(); var month = today.getMonth()+1; // +1 Because january is 0 var year = today.getFullYear(); 

And then its easy to make the compare.