php5.4转5.3被替换的函数

int preg_match ( string $pattern , string $subject [, array &$matches [, int $flags = 0 [, int $offset = 0 ]]] )

int ereg ( string $pattern , string $string [, array &$regs ] )

if(!ereg("^[0-9a-zA-Z\_]*$", $aa)) {
return false;
}

if(!preg_match("/^[0-9a-zA-Z\_]*$/", $callback)) {
return false;
}