The php pop up dialog box implements the redirect code

1. Implementation using js

 
if(!$this->userInfo){ 
$alert_msg = " Activation link error "; 
echo"<SCRIPT LANGUAGE='javascript'>alert('$alert_msg');window.location='$redirect_url';</SCRIPT>"; 
//redirect(base_url()); 
die; 

} 

2 php implementation

 
if(!$this->userInfo){ 
$alert_msg = " Activation link error "; 
echo"<SCRIPT LANGUAGE='javascript'>alert('$alert_msg');</SCRIPT>";// This has no popover effect  why?  add exit  There will be a popup window , It will be redirected later;  
redirect(base_url()); 
die; 
}