Go4Expert - time

hi
i want channge this code php languge
setInterval("next_page();",4500);

i want run this code

Code:

for($i=0;$i<5000;$i++)

{



fopen("a.txt","r");



// stop (1min) or javascript languages => setInterval("next_page();",8000);

// and run next 1 min 

}

please help me