Making HTML safer: details for toStaticHTML (HTML)

Artikel
09/07/2016

[ This article is for Windows 8.x and Windows Phone 8.x developers writing Windows Runtime apps. If you’re developing for Windows 10, see the latest documentation ]

As described in HTML, CSS, and JavaScript features and differences, HTML you inject into a page in your app's local context is filtered by the toStaticHTML method.

This security restriction affects these properties and methods:

The next sections describe which content is considered safe, and which is not.

(For info about how to work around HTML that doesn't make it through this filtering process, see HTML, CSS, and JavaScript features and differences.)

Elements

This list describes whether an element is considered safe. The system throws an exception when it finds an unsafe element.

Element	Allowed
Unknown tag	No
XML tag	No
<!-- -->	No
a	Yes
abbr	Yes
acronym	Yes
address	Yes
altGlyph	Yes
altGlyphDef	Yes
altGlyphItem	Yes
applet	No
area	Yes
article	Yes
aside	Yes
audio	Yes
b	Yes
base	No
bdi	Yes
bdo	Yes
bgsound	Yes
big	Yes
blink	No
blockquote	Yes
body	Yes
br	Yes
button	Yes
canvas	Yes
caption	Yes
center	Yes
circle	Yes
cite	Yes
clipPath	Yes
code	Yes
col	Yes
colGroup	Yes
color-profile	Yes
command*	Yes
comment	No
cursor	Yes
datalist	Yes
dd	Yes
defs	Yes
del	Yes
desc	Yes
details	Yes
dfn	Yes
dir	Yes
div	Yes
dl	Yes
dt	Yes
ellipse	Yes
em	Yes
embed	No
EVENT	No
feBlend	Yes
feColorMatrix	Yes
feComponentTransfer	Yes
feComposite	Yes
feConvolveMatrix	Yes
feDiffuseLighting	Yes
feDisplacementMap	Yes
feDistantLight	Yes
feFlood	Yes
feFuncA	Yes
feFuncB	Yes
feFuncG	Yes
feFuncG	Yes
feFuncR	Yes
feGaussianBlur	Yes
feImage	Yes
feMerge	Yes
feMergeNode	Yes
feMorphology	Yes
feOffset	Yes
fePointLight	Yes
feSpecularLighting	Yes
feSpotlight	Yes
feTile	Yes
feTurbulence	Yes
fieldset	Yes
figcaption	Yes
figure	Yes
filter	Yes
font-face	Yes
font-face-format	Yes
font-face-name	Yes
font-face-src	Yes
font-face-uri	Yes
font	Yes
footer	Yes
form	Yes
frame	No
frameset	No
g	Yes
glyph	Yes
glyphRef	Yes
h1	Yes
h2	Yes
h3	Yes
h4	Yes
h5	Yes
h6	Yes
head	Yes
header	Yes
hgroup	Yes
hkern	Yes
hr	Yes
html	Yes
i	Yes
iframe	No
image	Yes
img	Yes
input	Yes
ins	Yes
isindex	No
kbd	No
keygen*	Yes
label	Yes
layer	No
legend	Yes
li	Yes
line	Yes
linearGradient	Yes
link	No
listing	Yes
map	Yes
mark	Yes
marquee	Yes
mask	Yes
menu	Yes
meta	No
metadata	Yes
meter	Yes
missing-glyph	Yes
mpath	Yes
multicol	No
nav	Yes
nextid	Yes
nobr	Yes
noframes	Yes
noscript	No
object	No
ol	Yes
optGroup	Yes
option	Yes
output	Yes
p	Yes
param	No
path	Yes
pattern	Yes
plaintext	Yes
polygon	Yes
polyline	Yes
pre	Yes
progress	Yes
q	Yes
radialGradient	Yes
rb	No
rect	Yes
rp	No
rt	Yes
ruby	Yes
s	Yes
samp	Yes
script	No
section	Yes
select	Yes
small	Yes
source*	Yes
spacer	No
span	Yes
stop	Yes
strike	Yes
strong	Yes
style	Yes
sub	Yes
summary	Yes
sup	Yes
svg	Yes
switch	Yes
symbol	Yes
table	Yes
tBody	Yes
td	Yes
text	Yes
textArea	Yes
textPath	Yes
tfoot	Yes
th	Yes
thead	Yes
time	Yes
title	Yes
tr	Yes
track*	Yes
tref	Yes
tspan	Yes
tt	Yes
u	Yes
ul	Yes
var	No
video	Yes
view	Yes
vkern	Yes
wbr	Yes
XML	No
XMP	Yes

The meta element

Whether meta element is safe depends on what attributes and values it has. For example, some attributes can be used to redirect from the current page, but other attributes and values can do helpful things such as specifying the character set for a page.

For this reason, when the system finds a meta element, it processes the element and reads its attributes and values, then outputs a safe version of the meta tag. Regardless of where they were specified in the input HTML, the processed meta tags always appear as the first children of the head element.

Attributes

The next list describes whether an attribute is considered safe. The system throws an exception when it finds an unsafe attribute.

Attribute	Related Elements	Allowed
Unknown attributes		No
Attributes not legal in the tag		No
abbr	td, th	Yes
a-charset	form	No
a	form, input	No
accessKey	This attribute is allowed for all elements.	Yes
action	form	No
aggregator	td, th	No
align	caption	Yes
align	applet, iframe, img, input, object	Yes
align	legend	Yes
align	table	Yes
align	hr	Yes
align	div, h1, h2, h3, h4, h5, h6, p	Yes
align	col, colgroup, tbody, td, tfoot, th, thead, tr	Yes
alt	applet	Yes
alt	area, img	Yes
alt	input	Yes
archive	object	No
aria-*	aria attributes are allowed on all elements.	Yes
async		Yes
audio		Yes
autocomplete		Yes
autofocus		Yes
autoplay		Yes
autostart	embed	No
axis	td, th	No
background	body	Yes
background	TABLE	Yes
background	td, TH	Yes
behavior	MARQUEE	Yes
BGCOLOR	TABLE	Yes
BGCOLOR	TR	Yes
BGCOLOR	td, th	Yes
BGCOLOR	body	Yes
BGCOLOR	marquee	Yes
bgProperties	body	Yes
border	TABLE	Yes
border	frameset, iframe,	No
border	img, object	Yes
borderColor	frameset, table, td, th, tr	Yes
borderColorDark	table, td, th, tr	Yes
bordercolorlight	table, td, th, tr	Yes
cellPadding	TABLE	Yes
cellSpacing	TABLE	Yes
challenge		Yes
char	col, colgroup, tbody, td, tfoot, th, thead, tr	Yes
charoff	col, colgroup, tbody, td, tfoot, th, thead, tr	Yes
charset	a	Yes
charset	link, script	No
charset	meta	Yes
checked	input	Yes
cite	blockquote, q	Yes
cite	del, ins	Yes
class	all elements but base, head, html, meta, param, script, style, title	Yes
classid	object	No
clear	BR	Yes
code	applet	No
codebase	object	No
codebase	applet	No
codetype	object	No
color	basefont, font	Yes
color	hr	Yes
colfield	td, th	No
cols	FRAMESET	No
cols	TEXTAREA	No
colSpan	td, th	Yes
compact	DIR, dl, menu, ol, ul	Yes
content	META	No
coords	area	Yes
contenteditable	This attribute is allowed for all elements.	Yes
contextmenu	This attribute is allowed for all elements.
controls	IMG	No
coords	A	Yes
crosstab	TABLE	No
crosstabgrand	TABLE	No
data	object	No
data-win-bind	This attribute is allowed for all elements.	Yes
data-win-control	This attribute is allowed for all elements.	Yes
data-win-fragmentload	This attribute is allowed for all elements.	Yes
data-win-fragmentload	This attribute is allowed for all elements.	Yes
data-win-options	This attribute is allowed for all elements.	Yes
data-win-res	This attribute is allowed for all elements.	Yes
data-win-resid	This attribute is allowed for all elements.	Yes
datafield	td, th	No
dataFld	DIV	No
dataFormatAs	DIV	No
dataSrc	div, param	Yes
datetime	del, ins	Yes
declare	object	No
defer	SCRIPT	No
default		Yes
dir	This attribute is allowed for all elements.	Yes
direction	MARQUEE	Yes
dirname		Yes
disableddisabled	button, input, optgroup, option, select, textarea	Yes
disposition	LINK	No
draggable	This attribute is allowed on all elements.	Yes
dropzone	This attribute is allowed on all elements.	Yes
dynsrc	IMG	Yes
enctype	form	No
face	basefont, font	Yes
filter	td, th, tr	No
for	LABEL	No
form		Yes
formaction		Yes
formenctype		Yes
formmethod		Yes
formnovalidate		Yes
formtarget		Yes
formula	TD	No
frame	TABLE	No
frameBorder	frame, iframe	No
frameSpacing	frame, frameset, iframe	No
gutter	MULTICOL	No
headers	td, th	Yes
height	IFRAME	No
height	marquee	Yes
height	td, th, TR	Yes
height	img, object, input	Yes
height	applet	No
height	table	Yes
hidden	This attribute is allowed on all elements.	Yes
high		Yes
href	a, area, link	Yes
href	base	Yes
hreflang	a, link	Yes
hspace	applet, img, object	Yes
hspace	marquee	Yes
http-Equiv	META	No
id	This attribute is allowed on all elements.	Yes
icon		Yes
if	Not in W3C but supported in MSO	No
ifapp	Not in W3C but supported in MSO	No
ismap	img, input	No
keytype		Yes
kind		Yes
label	OPTION	Yes
label	OPTGROUP	Yes
lang	This attribute is allowed on all elements.	Yes
language	SCRIPT	No
left	LAYER	No
leftmargin	body	Yes
link	body	Yes
longdesc	IMG	Yes
longdesc	frame, iframe	No
loop	BGSOUND, embed, img, MARQUEE	Yes
low		Yes
lowsrc	IMG	Yes
manifest		Yes
marginHeight	frame, iframe	No
marginWidth	frame, iframe	No
max		Yes
maxLength	input	No
media	STYLE	No
media	LINK	No
method	form	No
methods	a, link	No
min		Yes
msallowcapture	This attribute is allowed on all elements.
msallowclip	This attribute is allowed on all elements.	Yes
mstagchanged	img	Yes
multiple	SELECT	Yes
name	All elements	No
noHref	AREA	No
novalidate		Yes
noResize	FRAME	No
noShade	HR	Yes
noWrap	td, th	Yes
ns	Not in W3C but supported in MSO	No
object	applet	No
on*	on* attributes (such as onabort) are not allowed on any element.	No
open		Yes
optimum		Yes
pagefield	td, th	No
pattern		Yes
placeholder		Yes
poster		Yes
prefix	Not in W3C but supported in MSO	No
preload		Yes
profile	HEAD	No
prompt	ISINDEX	No
pubdate		Yes
radiogroup		Yes
readonly	TEXTAREA	Yes
readonly	input	Yes
rel	a, link	Yes
required		Yes
rev	a, link	Yes
reversed		Yes
role	This attribute is allowed on all elements.	Yes
rowfield	td, th	No
rows	FRAMESET	No
rows	textarea	Yes
rowSpan	td, th	Yes
rules	TABLE	Yes
sandbox		Yes
scheme	META	Yes
scope	td, th	Yes
scoped		Yes
scrollamount	MARQUEE	Yes
scrolldelay	MARQUEE	Yes
scrolling	frame, iframe	No
seamless		Yes
security	iframe	Yes
selected	option	Yes
shape	AREA	Yes
shape	A	Yes
shapes	BGSOUND, img, input, MARQUEE, object, select, textarea	No
size	HR	No
size	FONT	Yes
size	input	Yes
size	BASEFONT	Yes
size	SELECT	Yes
sizes		Yes
span	COL	Yes
span	COLGROUP	Yes
spellcheck	This attribute is allowed on all elements.	Yes
src	SCRIPT	No
src	input	Yes
src	frame, iframe	No
src	IMG	Yes
src	bgsound	Yes
srcdoc		Yes
srclang		Yes
standby	object	No
start	OL	Yes
start	img	Yes
step		Yes
style	This attribute is allowed on all elements.	Yes
summary	table	Yes
subtotal	td, th	No
tabIndex	a, area, button, input, select, textarea	Yes
tabIndex	object	No
tabIndex	This attribute is allowed on all elements.	Yes
target	a, area, base, form, link	No
text	body	Yes
title	This attribute is allowed on all elements.	Yes
top	LAYER	No
topmargin	body	Yes
type	a, link	Yes
type	object	Yes
type	PARAM	Yes
type	SCRIPT	Yes
type	STYLE	Yes
type	input	No
type	li	Yes
type	OL	Yes
type	UL	Yes
type	BUTTON	No
usemap	img, input, object	Yes
vAlign	col, colgroup, tbody, td, tfoot, th, thead, tr	Yes
vAlign [c41]	caption	Yes
value	input	Yes
value	OPTION	Yes
value	PARAM	No
value	button	Yes
value	LI	Yes
valuetype	PARAM	No
version	html	Yes
vLink	body	Yes
volume	embed	No
vspace	applet, img, object	Yes
vspace [c44]	marquee	Yes
webpartid [c45]	div	Yes
wide	Not in W3C but supported in MSO	No
width	HR	Y
width	IFRAME	Yes
width	img, object, input	Yes
width	marquee	Yes
width	table	Yes
width	td, th	Yes
width	applet	No
width	col	Yes
width	colgroup	Yes
width	pre	Yes
wrap	TEXTAREA	Yes
x-ms-flow		Yes

CSS pseudo-classes, pseudo-elements, and rules

This list describes whether a pseudo-class, pseudo-element, or rule is considered safe. The system throws an exception when it finds an unsafe item.

pseudo-class, pseudo-element, or rule	Allowed
Unknown pseudo-classes, pseudo-elements and rules	No
!important	Yes
:active	Yes
:first-letter	Yes
:first-line	Yes
:hover	Yes
:link	Yes
:visited	Yes
@charset	No
@font-face	No
@import	No
@media	Yes
@page	Yes

CSS properties

The next list describes whether a CSS property is considered safe. The system throws an exception when it finds an unsafe property.

Property	Allowed
Unknown properties	No
CSS comments (/* comment */)	No
-ms-animation	Yes
-ms-animation-delay	Yes
-ms-animation-direction	Yes
-ms-animation-duration	Yes
-ms-animation-iteration-count	Yes
-ms-animation-name	Yes
-ms-animation-play-state	Yes
-ms-animation-timing-function	Yes
-ms-backface-visibility	Yes
-ms-behavior	Yes
-ms-box	Yes
-ms-box-align	Yes
-ms-content-zoom-chaining	Yes
-ms-content-zoom-max	Yes
-ms-content-zoom-max-style	Yes
-ms-content-zoom-min-style	Yes
-ms-content-zoom-snap-interval	Yes
-ms-content-zoom-snap-start	Yes
-ms-content-zoom-snap-style	Yes
-ms-content-zoom-snap-type	Yes
-ms-content-zooming	Yes
-ms-grid	Yes
-ms-grid-cell	Yes
-ms-grid-column	Yes
-ms-grid-column-align	Yes
-ms-grid-column-span	Yes
-ms-grid-columns	Yes
-ms-grid-row	Yes
-ms-grid-row-align	Yes
-ms-grid-row-span	Yes
-ms-perspective	Yes
-ms-perspective-origin	Yes
-ms-scroll-chaining	Yes
-ms-scroll-rails	Yes
-ms-scroll-snap-points-x	Yes
-ms-scroll-snap-points-y	Yes
-ms-scroll-snap-style	Yes
-ms-scroll-snap-type	Yes
-ms-scroll-snap-x	Yes
-ms-scroll-snap-x-interval	Yes
-ms-scroll-snap-x-start	Yes
-ms-scroll-snap-y	Yes
-ms-scroll-snap-y-interval	Yes
-ms-scroll-snap-y-start	Yes
-ms-scrollbar-3d-light-color	Yes
-ms-scrollbar-dark-shadow-color	Yes
-ms-transform	Yes
-ms-transform-origin	Yes
-ms-transform-style	Yes
-ms-transition	Yes
-ms-transition-delay	Yes
-ms-transition-duration	Yes
-ms-transition-property	Yes
-ms-transition-timing-function	Yes
accelerator	Yes
alignment-baseline	Yes
azimuth	Yes
background	Yes
background-attachment	Yes
background-clip	Yes
background-color	Yes
background-image	Yes
background-origin	Yes
background-position	Yes
background-position-x	Yes
background-position-y	Yes
background-repeat	Yes
background-size	Yes
baseline-shift	Yes
behavior	Yes
block-direction	Yes
border	Yes
border-bottom	Yes
border-bottom-color	Yes
border-bottom-left-radius	Yes
border-bottom-right-radius	Yes
border-bottom-style	Yes
border-bottom-width	Yes
border-collapse	Yes
border-color	Yes
border-left	Yes
border-left-color	Yes
border-left-style	Yes
border-left-width	Yes
border-radius	Yes
border-right	Yes
border-right-color	Yes
border-right-style	Yes
border-right-width	Yes
border-spacing	Yes
border-style	Yes
border-top	Yes
border-top-color	Yes
border-top-left-radius	Yes
border-top-right-radius	Yes
border-top-style	Yes
border-top-width	Yes
border-width	Yes
bottom	Yes
box-shadow	Yes
break-after	Yes
break-before	Yes
break-inside	Yes
caption-side	Yes
clear	Yes
clip	Yes
clip-bottom	Yes
clip-left	Yes
clip-path	Yes
clip-right	Yes
clip-rule	Yes
	Yes
color	Yes
color-interpolation-filters	Yes
column-count	Yes
column-fill	Yes
column-gap	Yes
column-rule	Yes
column-rule-color	Yes
column-rule-style	Yes
column-rule-width	Yes
column-span	Yes
column-width	Yes
columns	Yes
content	Yes
counter-increment	Yes
counter-reset	Yes
css-float	Yes
cue	Yes
cue-after	Yes
cue-before	Yes
cursor	Yes
direction	Yes
display	Yes
dominant-baseline	Yes
elevation	Yes
empty-cells	Yes
fill	Yes
fill-opacity	Yes
fill-rule	Yes
filter	Yes
float	Yes
flood-color	Yes
flood-opacity	Yes
font	Yes
font-color	Yes
font-emphasize	Yes
font-emphasize-position	Yes
font-emphasize-style	Yes
font-family	Yes
font-size	Yes
font-size-adjust	Yes
font-stretch	Yes
font-style	Yes
font-variant	Yes
font-weight	Yes
glyph-orientation-horizontal	Yes
glyphorientation-vertical	Yes
has-layout	Yes
height	Yes
horiz-align	Yes
ime-mode	Yes
kerning	Yes
language	Yes
layout-flow	Yes
layout-grid	Yes
layout-grid-char	Yes
layout-grid-line	Yes
layout-grid-mode	Yes
layout-grid-type	Yes
left	Yes
letter-spacing	Yes
line-break	Yes
line-height	Yes
list-image-1	Yes
list-image-2	Yes
list-image-3	Yes
list-style	Yes
list-style-image	Yes
list-style-position	Yes
list-style-type	Yes
margin	Yes
margin-bottom	Yes
margin-left	Yes
margin-right	Yes
margin-top	Yes
marker	Yes
marker-end	Yes
marker-mid	Yes
marker-offset	Yes
marker-start	Yes
marks	Yes
masks	Yes
max-width	Yes
min-height	Yes
min-width	Yes
mso-……….	No
nav-banner-image	Yes
navbutton_background_color	Yes
navbutton_home_hovered	Yes
navbutton_home_normal	Yes
navbutton_home_pushed	Yes
navbutton_horiz_hovered	Yes
navbutton_horiz_normal	Yes
navbutton_horiz_pushed	Yes
navbutton_next_hovered	Yes
navbutton_next_normal	Yes
navbutton_next_pushed	Yes
navbutton_prev_hovered	Yes
navbutton_prev_normal	Yes
navbutton_prev_pushed	Yes
navbutton_up_hovered	Yes
navbutton_up_normal	Yes
navbutton_up_pushed	Yes
navbutton_vert_hovered	Yes
navbutton_vert_normal	Yes
navbutton_vert_pushed	Yes
opacity	Yes
orphans	Yes
outline-color	Yes
outline-style	Yes
outline-width	Yes
overflow	Yes
overflow-x	Yes
overflow-y	Yes
padding	Yes
padding-bottom	Yes
padding-left	Yes
padding-right	Yes
padding-top	Yes
page	Yes
page-break-after	Yes
page-break-before	Yes
page-break-inside	Yes
panose-1	Yes
pause	Yes
pause-after	Yes
pause-before	Yes
pitch	Yes
pitch-range	Yes
pixel-bottom	Yes
pixel-height	Yes
pixel-left	Yes
pixel-right	Yes
pixel-top	Yes
pixel-width	Yes
play-during	Yes
pointer-events	Yes
pos-bottom	Yes
pos-height	Yes
pos-left	Yes
pos-right	Yes
pos-top	Yes
pos-width	Yes
position	Yes
punctuation-trim	Yes
punctuation-wrap	Yes
quotes	Yes
richness	Yes
right	Yes
row-span	Yes
ruby-align	Yes
ruby-overhang	Yes
ruby-position	Yes
scrollbar-3dlight-color	Yes
scrollbar-arrow-color	Yes
scrollbar-base-color	Yes
scrollbar-dark-shadow-color	Yes
scrollbar-face-color	Yes
scrollbar-highlight-color	Yes
scrollbar-shadow-color	Yes
scrollbar-track-color	Yes
separator-image	Yes
size	Yes
speak	Yes
speak-header	Yes
speak-numeral	Yes
speak-punctuation	Yes
speech-rate	Yes
src	Yes
stop-color	Yes
stop-opacity	Yes
stress	Yes
stroke	yes
stroke-dasharray	Yes
stroke-dashoffset	Yes
stroke-linecap	Yes
stroke-linejoin	Yes
stroke-miterlimit	Yes
stroke-opacity	Yes
stroke-width	Yes
style-float	Yes
tab-interval	Yes
table-border-color-dark	Yes
table-border-color-light	Yes
table-layout	Yes
tab-stops	Yes
text-anchor	Yes
text-align	Yes
text-align-last	Yes
text-autospace	Yes
text-combine	Yes
text-decoration	Yes
text-decoration-blink	Yes
text-decoration-line-through	Yes
text-decoration-none	Yes
text-decoration-overline	Yes
text-decoration-underline	Yes
text-effect	Yes
text-fit	Yes
text-indent	Yes
text-justify	Yes
text-justify-trim	Yes
text-kashida	Yes
text-kashida-space	Yes
text-line-through	Yes
text-overflow	Yes
text-shadow	Yes
text-transform	Yes
text-underline	Yes
text-underline-color	Yes
text-underline-position	Yes
text-underline-style	Yes
top	Yes
top-bar-button	Yes
unicode-bidi	Yes
version	Yes
vert-align	Yes
vertical-align	Yes
visibility	Yes
voice-family	Yes
volume	Yes
white-space	Yes
width	Yes
windows	Yes
word-break	Yes
word-spacing	Yes
word-wrap	Yes
writing-mode	Yes
z-index	Yes
zoom	Yes

Smart tags

toStaticHTML removes all smart tags and related attributes.

URIs and Schemes

toStaticHTML blocks these schemes and removes them from HTML it processes:

about:
cdl:
data:
dvd:
file:
its:
javascript:
local:
mhtml:
mk:
ms-help:
ms-its:
res:
tv:
vbscript:

URIs must be well-formed. toStaticHTML blocks malformed URIs and removes them from HTML it processes.

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