Session with microtime

hello, I'm writting a script where I use the function microtime with sessions and I have a problem. This is my code: if( $_SESSION['uperm'] == '1' ){ $t_start = microtime(1); } (....) if( $_SESSION['uperm'] == '1' ){ $t_end = microtime(1) - $t_start;

 $time .= "\n      " . '<P>This page was loaded in ' .

number_format($t_end, 3) . ' seconds.</P>'; } And when I log with any account (admin or user) is "echoed" to me something like this: "This page was loaded in 1,177,003,846.594 seconds." This is too much because the page isn't loaded in this time. And when I refresh the page it appears: "This page was loaded in 0.012 seconds." Why is this? I can't explain. And this started to appear when I put the "if" to check the user permissions. If I "turn off" the "if" it'll run normally. Can anyone explain why is that? Thanks in advance.