Getting time difference between two times in PHP

$val1 = '2014-03-18 10:34:09.939';$val2 = '2014-03-18 10:34:09.940';
$datetime1 = new DateTime($val1);$datetime2 = new DateTime($val2);
echo "

"

;var_dump($datetime1->diff($datetime2));

if($datetime1 > $datetime2)
  echo "1 is bigger";
else
  echo "2 is bigger";

?>

How to apply css styles to codeigniter dropdown?

form_dropdown('dropdown', $options, $selected, 'style="width: 240px; font-size: 13px"');

You could just as easily add a class to the  and then add the styles in your stylesheet:

form_dropdown('dropdown', $options, $selected, 'class="foo"');

In either case, if you don't have a value for $selected, set it to array()

form_dropdown('dropdown', $options, array(), 'style="width: 240px; font-size: 13px"');

Although you could get away setting it to null or '' for convenience.

What are the main differences between InnoDB and MyISAM

InnoDB has row-level locking, MyISAM can only do full table-level locking. 

InnoDB has better crash recovery. 

MyISAM has FULLTEXT search indexes, InnoDB did not until MySQL 5.6 (Feb 2013).

InnoDB implements transactions, for foreign  keys and relationship constraints, MyISAM does not