安全过滤函数，用于过滤危险字符

function safe_replace($string) {

 $string = str_replace('
','',$string);

 $string =
str_replace(''','',$string);

 $string =
str_replace(''','',$string);

 $string =
str_replace('*','',$string);

 $string =
str_replace('"','"',$string);

 $string =
str_replace("'",'',$string);

 $string =
str_replace('"','',$string);

 $string =
str_replace(';','',$string);

 $string =
str_replace('<','<',$string);

 $string =
str_replace('>','>',$string);

 $string =
str_replace("{",'',$string);

 $string =
str_replace('}','',$string);

 return $string;

}