title: Check if date is in the next 3 days PHP
body: <p>I have a date stored in my DB (due_date)
  I am wanting to write a script that checks if the due_date is in the next 3 days</p>
  
  <p>From checking online (google) i have found some code but it doesnt seem to work, see below</p>
  
  <pre><code>if (time() - filemtime($due_date) &gt;= 3 * 86400) 
  
  {
    echo" Invoice $id is due in the next 3 days&lt;br /&gt;";
  }
  else
  {
  echo" Invoice $id not due in the next 3 days &lt;/br&gt;";
  }
  </code></pre>
  
  <p>$due_date contains a date in the format 01/01/2015</p>
  
  <p>Please can someone help with this? P.s I am a newbie!</p>
  
  <p>Thanks</p>