title: Input Type Date validation 18 years old below
body: <p>I'm having trouble with validation of input type="date". It shouldn't accept 18 years old below. Could you please help me? Thank you.</p>
  
  <p>I google and search the forum I haven't found the answer. 
  I tried to validate it in the next page using PHP but my professor told me I must validate it in the same page. Like onchange it must be validated.</p>
  
  <pre><code>&lt;input type="date" name="bday" id="bday" value=""&gt;
  </code></pre>