Blank screen error is such an annoying error in web programming. Since this error didn’t tell us what the problem exactly is. This problem occurred when I changed my working environment to ubuntu. In ubuntu I use the new one of php which is php 5.3.6, but unfortunately my CI is still in the old version. After checked out from the svn server and changed the application config, I launch the browser to run my application. It’s blank, no error, no warning, just blank at all. I thought it was my apache problem so I tried to install a fresh copy of the latest CI. I found that the problem not at my apache but in the CI itself.
So how did I resolve this problem? Ok first open file index.php and find this line
replace the code above with this one. And try to refresh the browser and it will show what the error is.
error_reporting(E_ALL & ~E_DEPRECATED);
The problem had not been totally solved, because the solution above only for displaying the error. With this tricky way, CI usually tell that the error is about the URI character permission like this one below.
The URI you submitted has disallowed characters.
Well, to fix this problem find this line in the CI config file .
$config['permitted_uri_chars'] = 'a-z 0-9~%\.\:_\-';
Just remove those characters so it will be look like this.
$config['permitted_uri_chars'] = '';
Actually it’s not recommended solution, because it will open the application vulnerability. But it works😀 after all. Another solution perhaps is upgrading the CI core.