Perl
#! The first function takes the negative approach.
#! Use a list of bad characters to filter the data
sub FilterNeg {
local( $fd ) = @_;
$fd =~ s/[\<\>\"\'\%\;\)\(\&\+]//g;
return( $fd ) ;
}
#! The second function takes the positive approach.
#! Use a list of good characters to filter the data
sub FilterPos {
local( $fd ) = @_;
$fd =~ tr/A-Za-z0-9\ //dc;
return( $fd ) ;
}
$Data = "This is a test string＜script＞";
$Data = &FilterNeg( $Data );
print "$Data\n";
$Data = "This is a test string＜script＞";
$Data = &FilterPos( $Data );
print "$Data\n";
第五步：检查Cookies值
攻击者还可能将恶意内容写入cookie中，因此，Web开发者应该仔细地检查接受的cookie值，并使用上面提及的过滤技术以验证它们是否包含了恶意内容。
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