<?php
var_dump(is_file('a_file.txt')) . "\n";
var_dump(is_file('/usr/bin/')) . "\n";
?>

<?php
function isfile($file){
return preg_match('/^[^.^:^?^-][^:^?]*.(?i)' . getexts() . '$/',$file);
//first character cannot be . : ? - subsequent characters can't be a : ?
//then a . character and must end with one of your extentions
//getexts() can be replaced with your extentions pattern
}
function getexts(){
//list acceptable file extensions here
return '(app|avi|doc|docx|exe|ico|mid|midi|mov|mp3|
mpg|mpeg|pdf|psd|qt|ra|ram|rm|rtf|txt|wav|word|xls)';
}
echo isfile('/Users/YourUserName/Sites/index.html');
?>

<?php
function deletefolder($path)
{
if ($handle=opendir($path))
{
while (false!==($file=readdir($handle)))
{
if ($file<>"." AND $file<>"..")
{
if (is_file($path.'/'.$file))
{
@unlink($path.'/'.$file);
}
if (is_dir($path.'/'.$file))
{
deletefolder($path.'/'.$file);
@rmdir($path.'/'.$file);
}
}
}
}
}
?>