HTML – URL Encoding

HTML – URL Encoding

URL encoding is the practice of translating unprintable characters or characters with special meaning within URLs to a representation that is unambiguous and universally accepted by web browsers and servers. These characters include −

  • ASCII control characters − Unprintable characters typically used for output control. Character ranges 00-1F hex (0-31 decimal) and 7F (127 decimal). A complete encoding table is given below.
  • Non-ASCII control characters − These are characters beyond the ASCII character set of 128 characters. This range is part of the ISO-Latin character set and includes the entire “top half” of the ISO-Latin set 80-FF hex (128-255 decimal). A complete encoding table is given below.
  • Reserved characters − These are special characters such as the dollar sign, ampersand, plus, common, forward slash, colon, semi-colon, equals sign, question mark, and “at” symbol. All of these can have different meanings inside a URL so need to be encoded. A complete encoding table is given below.
  • Unsafe characters − These are space, quotation marks, less than symbol, greater than symbol, pound character, percent character, Left Curly Brace, Right Curly Brace, Pipe, Backslash, Caret, Tilde, Left Square Bracket, Right Square Bracket, Grave Accent. These character present the possibility of being misunderstood within URLs for various reasons. These characters should also always be encoded. A complete encoding table is given below.

The encoding notation replaces the desired character with three characters: a percent sign and two hexadecimal digits that correspond to the position of the character in the ASCII character set.

Example

One of the most common special characters is a white space. You can’t type a space in a URL directly. A space position in the character set is 20 hexadecimals. So you can use %20 in place of a space when passing your request to the server.

http://www.example.com/new%20pricing.htm

This URL actually retrieves a document named “new pricing.htm” from the www.example.com

ASCII Control Characters Encoding

This includes the encoding for character ranges 00-1F hex (0-31 decimal) and 7F (127 decimal)

Decimal Hex Value Character URL Encode
0 00 %00
1 01 %01
2 02 %02
3 03 %03
4 04 %04
5 05 %05
6 06 %06
7 07 %07
8 08 backspace %08
9 09 tab %09
10 0a linefeed %0a
11 0b %0b
12 0c %0c
13 0d carriage return %0d
14 0e %0e
15 0f %0f
16 10 %10
17 11 %11
18 12 %12
19 13 %13
20 14 %14
21 15 %15
22 16 %16
23 17 %17
24 18 %18
25 19 %19
26 1a %1a
27 1b %1b
28 1c %1c
29 1d %1d
30 1e %1e
31 1f %1f
127 7f %7f

Non-ASCII control characters encoding

This includes the encoding for the entire “top half” of the ISO-Latin set 80-FF hex (128255 decimal.)

Decimal Hex Value Character URL Encode
128 80 %80
129 81  %81
130 82 %82
131 83 ƒ %83
132 84 %84
133 85 %85
134 86 %86
135 87 %87
136 88 ˆ %88
137 89 %89
138 8a Š %8a
139 8b %8b
140 8c Π%8c
141 8d  %8d
142 8e Ž %8e
143 8f  %8f
144 90  %90
145 91 %91
146 92 %92
147 93 %93
148 94 %94
149 95 %95
150 96 %96
151 97 %97
152 98 ˜ %98
153 99 %99
154 9a š %9a
155 9b %9b
156 9c œ %9c
157 9d  %9d
158 9e ž %9e
159 9f Ÿ %9f
160 a0 %a0
161 a1 ¡ %a1
162 a2 ¢ %a2
163 a3 £ %a3
164 a4 ¤ %a4
165 a5 ¥ %a5
166 a6 ¦ %a6
167 a7 § %a7
168 a8 ¨ %a8
169 a9 © %a9
170 aa ª %aa
171 ab « %ab
172 ac ¬ %ac
173 ad ­ %ad
174 ae ® %ae
175 af ¯ %af
176 b0 ° %b0
177 b1 ± %b1
178 b2 ² %b2
179 b3 ³ %b3
180 b4 ´ %b4
181 b5 µ %b5
182 b6 %b6
183 b7 · %b7
184 b8 ¸ %b8
185 b9 ¹ %b9
186 ba º %ba
187 bb » %bb
188 bc ¼ %bc
189 bd ½ %bd
190 be ¾ %be
191 bf ¿ %bf
192 c0 À %c0
193 c1 Á %c1
194 c2 Â %c2
195 c3 Ã %c3
196 c4 Ä %c4
197 c5 Å %c5
198 c6 Æ %v6
199 c7 Ç %c7
200 c8 È %c8
201 c9 É %c9
202 ca Ê %ca
203 cb Ë %cb
204 cc Ì %cc
205 cd Í %cd
206 ce Î %ce
207 cf Ï %cf
208 d0 Ð %d0
209 d1 Ñ %d1
210 d2 Ò %d2
211 d3 Ó %d3
212 d4 Ô %d4
213 d5 Õ %d5
214 d6 Ö %d6
215 d7 × %d7
216 d8 Ø %d8
217 d9 Ù %d9
218 da Ú %da
219 db Û %db
220 dc Ü %dc
221 dd Ý %dd
222 de Þ %de
223 df ß %df
224 e0 à %e0
225 e1 á %e1
226 e2 â %e2
227 e3 ã %e3
228 e4 ä %e4
229 e5 å %e5
230 e6 æ %e6
231 e7 ç %e7
232 e8 è %e8
233 e9 é %e9
234 ea ê %ea
235 eb ë %eb
236 ec ì %ec
237 ed í %ed
238 ee î %ee
239 ef ï %ef
240 f0 ð %f0
241 f1 ñ %f1
242 f2 ò %f2
243 f3 ó %f3
244 f4 ô %f4
245 f5 õ %f5
246 f6 ö %f6
247 f7 ÷ %f7
248 f8 ø %f8
249 f9 ù %f9
250 fa ú %fa
251 fb û %fb
252 fc ü %fc
253 fd ý %fd
254 fe þ %fe
255 ff ÿ %ff

Reserved Characters Encoding

Following is the table to be used to encode reserved characters.

Decimal Hex Value Char URL Encode
36 24 $ %24
38 26 & %26
43 2b + %2b
44 2c , %2c
47 2f / %2f
58 3a : %3a
59 3b ; %3b
61 3d = %3d
63 3f ? %3f
64 40 @ %40

Unsafe Characters Encoding

Following is the table to be used to encode unsafe characters.

Decimal Hex Value Char URL Encode
32 20 space %20
34 22 %22
60 3c < %3c
62 3e > %3e
35 23 # %23
37 25 % %25
123 7b { %7b
125 7d } %7d
124 7c | %7c
92 5c \ %5c
94 5e ^ %5e
126 7e ~ %7e
91 5b [ %5b
93 5d ] %5d
96 60 ` %60

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