How to Resolve PHP Linefeeds (\n) Not Working issue

When you run a PHP script in a browser, it will be rendered as HTML by default. If the books you’re using show otherwise, then either the code or the illustration is inaccurate. You can use “view source” to view what was sent to the browser and you’ll see that your line feeds are present.

<?php
echo "Line 1\nLine 2";
?>

This will render in your browser as:

Line 1 Line 2

If you need to send plain text to your browser, you can use something like:

<?php
header('Content-type: text/plain');
echo "Line 1\nLine 2";
?>

This will output:

Line 1
Line 2

if/else conditions in CSS?

here is list of operators are available

lt = less than operator lte = less than or equal to gt = greater than gte = greater than or equal to ! = the NOT operator () = subexpression operator & = the AND operator | = the OR operator true = evaluates to true false = evaluates to false

you can use this like this

<!--[if lt IE 7 ]>
  <p>Only less than IE 7 will see this</p>
<![endif]-->


<!--[if gte IE 6 ]>
 <p>Only  IE 6 and greater will see this</p>
<![endif]--> 

Check Session is Set or Not in Codeigniter ?

As per CodeIgniter Documentation If Session in not set it return FALSE .

if ($this->session->userdata('variable') !== FALSE) { 

         echo 'Variable is set';

 } else { 

        echo 'Variable is not set'; 

}