Lesson 19

Entities continued

Using special characters as a code for email addresses

Spammers use programs that scan web pages on the Internet for email addresses. They look for alpha-numeric characters and for the 'at' character, i.e. '@'. Coding these characters makes these programs miss the addresses. I used to use the codes shown in the table below, alternating the decimal and hexadecimal versions, in case spammers catch on to this trick.

I understand that entities are no longer safe for displaying email addresses and so in future email addresses on this site are displayed in the form of graphics.

char hex dec   x20 32 ! x21 33 " x22 34 # x23 35 $ x24 36 % x25 37 & x26 38 ' x27 39 ( x28 40 ) x29 41 * x2a 42 + x2b 43 , x2c 44 - x2d 45 . x2e 46 / x2f 47

char hex dec 0 x30 48 1 x31 49 2 x32 50 3 x33 51 4 x34 52 5 x35 53 6 x36 54 7 x37 55 8 x38 56 9 x39 57 : x3a 58 ; x3b 59 < x3c 60 = x3d 61 > x3e 62 ? x3f 63

char hex dec @ x40 64 A x41 65 B x42 66 C x43 67 D x44 68 E x45 69 F x46 70 G x47 71 H x48 72 I x49 73 J x4a 74 K x4b 75 L x4c 76 M x4d 77 N x4e 78 O x4f 79

char hex dec P x60 80 Q x61 81 R x62 82 S x63 83 T x64 84 U x65 85 V x66 86 W x67 87 X x68 88 Y x69 89 Z x6a 90 [ x6b 91 \ x6c 92 ] x6d 93 ^ x6e 94 - x6f 95

char hex dec ' x60 96 a x61 97 b x62 98 c x63 99 d x64 100 e x65 101 f x66 102 g x67 103 h x68 104 i x69 105 j x6a 106 k x6b 107 l x6c 108 m x6d 109 n x6e 110 o x6f 111

char hex dec p x70 112 q x71 113 r x72 114 s x73 115 t x74 116 u x75 117 v x76 118 w x77 119 x x78 120 y x79 121 z x7a 122 { x7b 123 | x7c 124 } x7d 125 ~ x7e 126   x7f 127

Now decode the following:

Well Done

Check your answer.