Codeigniter Prevent Back

 <div dir="ltr" style="text-align: left;" trbidi="on">  
 Put this code in each Controller<br />  
 <br />  
 public function __construct()<br />  
 <span class="Apple-tab-span" style="white-space: pre;"> </span>{<br />  
 <span class="Apple-tab-span" style="white-space: pre;"> </span>parent::__construct();<br />  
 <span class="Apple-tab-span" style="white-space: pre;"> </span>$this-&gt;output-&gt;set_header('Last-Modified:'.gmdate('D, d M Y H:i:s').'GMT');<br />  
 <span class="Apple-tab-span" style="white-space: pre;"> </span>$this-&gt;output-&gt;set_header('Cache-Control: no-store, no-cache, must-revalidate');<br />  
 <span class="Apple-tab-span" style="white-space: pre;"> </span>$this-&gt;output-&gt;set_header('Cache-Control: post-check=0, pre-check=0',false);<br />  
 <span class="Apple-tab-span" style="white-space: pre;"> </span>$this-&gt;output-&gt;set_header('Pragma: no-cache');<br />  
 <span class="Apple-tab-span" style="white-space: pre;"> </span>}</div>