CTAN Markdown: Inline HTML

In general inline HTML is sanitized and the result is passed to the output.

abc <b>def</b> ghi  

This sanitizing means that only white-listed HTML tags and white-listed tag parameters are passed through. Black-listed HTML tags are deleted. Unknown tags are escaped, i.e. the opening < and closing > are translated to HTML entities.

abc <bx>def</bx> ghi  

Not white-listed tag parameters are suppressed.

Black-listed tags are suppressed either with or without their body.

The following list contains the white-listed tags and attributes:

Tag	Attributes
a	class, id, style, name, href, title
abbr	class, id, style
acronym	class, id, style
address	class, id, style
area	class, id, style
b	class, id, style
bdo	class, id, style
big	class, id, style
blockquote	class, id, style
br	class, id, style
caption	class, id, style
center	class, id, style
cite	class, id, style
code	class, id, style
col	class, id, style
colgroup	class, id, style
dd	class, id, style
del	class, id, style
dfn	class, id, style
dir	class, id, style
div	class, id, style, align
dl	class, id, style
dt	class, id, style
em	class, id, style
font	class, id, style, color, face, size
h1	class, id, style
h2	class, id, style
h3	class, id, style
h4	class, id, style
h5	class, id, style
h6	class, id, style
hr	class, id, style
i	class, id, style
img	class, id, style, src, width, height, alt, title
ins	class, id, style
isindex	class, id, style
kbd	class, id, style
legend	class, id, style
li	class, id, style
map	class, id, style
noframes	class, id, style
noscript	class, id, style
ol	class, id, style
optgroup	class, id, style
p	class, id, style, align
pre	class, id, style
q	class, id, style
s	class, id, style
samp	class, id, style
small	class, id, style
span	class, id, style
strike	class, id, style
strong	class, id, style
sub	class, id, style
sup	class, id, style
table	class, id, style
tbody	class, id, style
td	class, id, style, align
tfoot	class, id, style
th	class, id, style, align
thead	class, id, style
tr	class, id, style
tt	class, id, style
u	class, id, style
ul	class, id, style
var	class, id, style

Note:

In contrast to GFM the table tags are not forbidden.

The following list contains the black-listed tags and the unit which is suppressed:

Tag	Supresses
!DOCTYPE	skip tag
applet	ignore body
base	skip tag
basefont	skip tag
body	skip tag
button	skip tag
fieldset	skip tag
form	skip tag
frame	ignore body
frameset	ignore body
head	ignore body
html	skip tag
iframe	ignore body
input	skip tag
label	skip tag
link	skip tag
menu	skip tag
meta	skip tag
object	ignore body
option	skip tag
param	skip tag
script	ignore body
select	skip tag
style	ignore body
textarea	skip tag
title	ignore body

As you can see the “dangerous” JavaScript tags and attributes are filtered out.