HTML Encoder / Decoder

Encode and decode a piece of text to its HTML equivalent.

Output

Input some data to be encoded or decoded.

Description

The HTML character encoder converts all applicable characters to their corresponding HTML entities. Certain characters have special significance in HTML and should be converted to their correct HTML entities to preserve their meanings. For example, it is not possible to use the < character as it is used in the HTML syntax to create and close tags. It must be converted to its corresponding &lt; HTML entity to be displayed in the content of an HTML page. HTML entity names are case sensitive.

Reserved entities, symbols and characters in HTML

Character Entity Name Description
" &quot; quotation mark
' &apos; apostrophe 
& &amp; ampersand
< &lt; less-than
> &gt; greater-than
  &nbsp; non-breaking space
¡ &iexcl; inverted exclamation mark
¢ &cent; cent
£ &pound; pound
¤ &curren; currency
¥ &yen; yen
¦ &brvbar; broken vertical bar
§ &sect; section
¨ &uml; spacing diaeresis
© &copy; copyright
ª &ordf; feminine ordinal indicator
« &laquo; angle quotation mark (left)
¬ &not; negation
­ &shy; soft hyphen
® &reg; registered trademark
¯ &macr; spacing macron
° &deg; degree
± &plusmn; plus-or-minus 
² &sup2; superscript 2
³ &sup3; superscript 3
´ &acute; spacing acute
µ &micro; micro
&para; paragraph
· &middot; middle dot
¸ &cedil; spacing cedilla
¹ &sup1; superscript 1
º &ordm; masculine ordinal indicator
» &raquo; angle quotation mark (right)
¼ &frac14; fraction 1/4
½ &frac12; fraction 1/2
¾ &frac34; fraction 3/4
¿ &iquest; inverted question mark
× &times; multiplication
÷ &divide; division
À &Agrave; capital a, grave accent
Á &Aacute; capital a, acute accent
 &Acirc; capital a, circumflex accent
à &Atilde; capital a, tilde
Ä &Auml; capital a, umlaut mark
Å &Aring; capital a, ring
Æ &AElig; capital ae
Ç &Ccedil; capital c, cedilla
È &Egrave; capital e, grave accent
É &Eacute; capital e, acute accent
Ê &Ecirc; capital e, circumflex accent
Ë &Euml; capital e, umlaut mark
Ì &Igrave; capital i, grave accent
Í &Iacute; capital i, acute accent
Î &Icirc; capital i, circumflex accent
Ï &Iuml; capital i, umlaut mark
Ð &ETH; capital eth, Icelandic
Ñ &Ntilde; capital n, tilde
Ò &Ograve; capital o, grave accent
Ó &Oacute; capital o, acute accent
Ô &Ocirc; capital o, circumflex accent
Õ &Otilde; capital o, tilde
Ö &Ouml; capital o, umlaut mark
Ø &Oslash; capital o, slash
Ù &Ugrave; capital u, grave accent
Ú &Uacute; capital u, acute accent
Û &Ucirc; capital u, circumflex accent
Ü &Uuml; capital u, umlaut mark
Ý &Yacute; capital y, acute accent
Þ &THORN; capital THORN, Icelandic
ß &szlig; small sharp s, German
à &agrave; small a, grave accent
á &aacute; small a, acute accent
â &acirc; small a, circumflex accent
ã &atilde; small a, tilde
ä &auml; small a, umlaut mark
å &aring; small a, ring
æ &aelig; small ae
ç &ccedil; small c, cedilla
è &egrave; small e, grave accent
é &eacute; small e, acute accent
ê &ecirc; small e, circumflex accent
ë &euml; small e, umlaut mark
ì &igrave; small i, grave accent
í &iacute; small i, acute accent
î &icirc; small i, circumflex accent
ï &iuml; small i, umlaut mark
ð &eth; small eth, Icelandic
ñ &ntilde; small n, tilde
ò &ograve; small o, grave accent
ó &oacute; small o, acute accent
ô &ocirc; small o, circumflex accent
õ &otilde; small o, tilde
ö &ouml; small o, umlaut mark
ø &oslash; small o, slash
ù &ugrave; small u, grave accent
ú &uacute; small u, acute accent
û &ucirc; small u, circumflex accent
ü &uuml; small u, umlaut mark
ý &yacute; small y, acute accent
þ &thorn; small thorn, Icelandic
ÿ &yuml; small y, umlaut mark

PHP code sample

htmlentities
PHP 4, PHP 5

htmlentities - Convert all applicable characters to HTML entities

string htmlentities ( string $string  [, int $quote_style = ENT_COMPAT  [, string $charset  [, bool $double_encode = true  ]]] )

This function is identical to htmlspecialchars() in all ways, except with htmlentities(), all characters which have HTML character entity equivalents are translated into these entities.
If you're wanting to decode instead (the reverse) you can use html_entity_decode().

.NET Framework code sample

HttpUtility.HtmlEncode Method (String)

.NET Framework 4, 3.5, 3.0, 2.0, 1.1, 1.0

HttpUtility.HtmlEncode Method (String) - Converts a string to an HTML-encoded string

myEncodedString = HttpUtility.HtmlEncode(myString);

HTML encoding makes sure that text is displayed correctly in the browser and not interpreted by the browser as HTML. For example, if a text string contains a less than sign (<) or greater than sign (>), the browser would interpret these characters as the opening or closing bracket of an HTML tag. When the characters are HTML encoded, they are converted to the strings &lt; and &gt;, which causes the browser to display the less than sign and greater than sign correctly.

References and links of interest