Comparison of layout engines (non-standard HTML)

The following tables compare deprecated and proprietary HTML elements and attributes compatibility and support for a number of layout engines. Please see the individual products' articles for further information. Unless otherwise specified in footnotes, comparisons are based on the stable versions without any add-ons, extensions or external programs.

In the early years of the World Wide Web, the standards which today are used in most web browsers and web pages were mostly non-existent. Different browsers and HTML editors were being offered by competing vendors such as Netscape, Microsoft and WebTV, all of whom had their own ideas for how web sites should be constructed. These varying features resulted in web developers coding for specific web browsers, using elements which could often be recognized by only one browser.

The WebTV and IBM WebExplorer inventions have never seen adoption by mainstream browsers.

Explanation of the tables

Engine nomenclature

Rather than the names of web browsers and HTML to PDF converters, the names of the underlying engines are used. Some of the software and online converters that use the various engines are listed below.

Layout engine	Release version	Preview version	Used by
Amaya	11.4.7[1]	N/A	No longer developed; Amaya
Blink	537.36	source code[note 1]	Chromium/Chrome (28+), Opera (15+), Yandex, Liebao and Samsung Browser .
EdgeHTML	13.10586 [2]	N/A	Microsoft Edge, Universal Windows Platform (UWP) JavaScript apps
Gecko	44.0.2 (February 11, 2016[3]) [±] ESR 38.6.1 (February 11, 2016[4]) [±]	Beta 45.0 Beta 6 (February 16, 2016[5][6]) [±] Developer Edition 46.0a2 (January 26, 2016[7]) [±] daily release Nightly 47.0a1 (January 25, 2016[8]) [±] daily release	All Mozilla software, including Firefox; SeaMonkey and Galeon; Camino; K-Meleon; Flock (up to 2.x); Debian IceWeasel; GNU IceCat (formerly GNU IceWeasel); Cyberfox; Icedove, Iceape and Iceowl; Firefox for mobile ("Fennec"). Also used by the Maple platform in 2010 and 2011 Samsung "SmartTV" devices which are based on the build used in Firefox 3.0. Nokia Asha platform is also using Gecko for web apps rendering.
KHTML	4.12.3[9]	N/A	Konqueror[note 2]
Presto	2.12.388	N/A	No longer developed; Opera and Opera Mobile use Blink now; Nintendo DS & DSi Browser; Internet Channel
Prince	10	20160109	HTML to PDF converters: Prince (previously called PrinceXML), DocRaptor. The information in the Prince columns is also true of Prince for Books, a related layout engine.
Tasman	(IE 5.2.3 for Mac)	N/A	No longer developed (aborted in 2003); Internet Explorer 5+ for Mac OS X
Trident	7.0 (IE 11)	N/A	Internet Explorer and other Internet Explorer shells like Maxthon (Microsoft Windows operating systems only), Windows Phone 8
WebKit	534.20	nightly build[note 3]	Tizen (both OS and browser), Safari (both desktop and mobile), Google Chrome (before 28), Maxthon 3, Shiira, iCab 4, OmniWeb 5.5+, Web, Adobe AIR, Midori, Adobe Dreamweaver CS4 and CS5, Android browser, Palm webOS browser, Symbian S60 browser, OWB, Steam, Rekonq, Arora, Flock (version 3+), RockMelt, Dolphin Browser, Sleipnir, Konqueror[note 2]. Used by the LG Smart TV platform to enable web content on TVs. HTML to PDF converters: wkhtmltopdf, PhantomJS, Pdfcrowd[10], http://www.online-convert.com/[11].

1. "chromium / chromium/blink". chromium.googlesource.com. Google. Retrieved 2014-05-27.
2. In Konqueror, the user can switch the used layout engine.
3. "WebKit Nightly Builds". webkit.org. Retrieved 2014-05-27.

Values

Values indicate the level of support in the most recent version of the layout engine, or (if a version number is given) in the specified version. Version numbers without any other value indicate the version at which the layout engine first fully supported the feature.

Value	Meaning
Yes	Indicates that the layout engine fully supports this property/element when valid values are used.
No	Indicates that the property/element is completely ignored.
Partial	Indicates that the property/element is understood, but that not all values are supported. Supported values are implemented correctly.
Incorrect	Indicates that the property/element is understood, but that it is not implemented correctly in all cases.
Experimental	Indicates that the property/element is understood, but supported under an alternate name. May be incomplete or buggy.
Dropped	Indicates that the property/element is no longer supported.
Nightly build	Indicates that the property/element is supported to some extent in an experimental/nightly build. Future support is expected.
Depends	Indicates that the property/element is supported only on certain platforms, or if certain settings are configured.

Deprecated HTML elements

Element	Function	Supported first by	Deprecated in HTML version	Alternative solution	Trident	Gecko	WebKit	KHTML	Presto
applet	Insert an applet	HotJava	4[12]	embed, object	<3.1^[IE 4.0]	1.7	Yes	Yes	1.0
basefont	Sets font styles	Internet Explorer	4	CSS	<3.1^[IE 3.0]	No[13]	85		Yes
center	Centers contents	Netscape[14]	4	CSS	3.1	Yes	Yes
dir	Directory list	?	4	ul, ol
font	Applies font styles	Netscape	4	CSS
isindex[15]	Adds a search field	?	4	input type="search"	<3.1^[IE 5.5]	1.7	312		Partial
listing	Displays preformatted text	IETF	2	pre, samp, code, CSS	3.1		125	3.3	Yes
menu	Menu list	?	4	ul, ol		Yes	Yes	Yes
plaintext	Designates that all HTML be ignored, and to display the page as is	?	3.2	The text/plain MIME type
s	Strike-through	?	4	del, CSS	<3.1^[IE 4.0]	1.7			1.0
strike	Strike-through	?	4	del, CSS
u	Underline	?	4	CSS
xmp	Similar to pre and plaintext, but ignores all HTML within and displays as is	?	2	pre, samp, code	<3.1^[IE 3.0]		125	3.3

Deprecated HTML attributes

Attribute	Element	Alternative solution	Trident	Gecko	WebKit	KHTML	Presto
align	caption, div, fieldset, h1, h2, h3, h4, h5, h6, hr, img, input, legend, p, object, table	CSS	3.1	Yes	Yes	Yes	Yes
alink	body	CSS			No
background	body	CSS			Yes
bgcolor	body, table, tr, td, th	CSS
border	img, object	CSS			Partial[note 1]
clear	br	CSS			No
compact	dl, ul, ol	CSS	No	No
color	basefont, font	CSS	3.1	Partial[note 2][13]	Partial[note 2]
height	td, th	CSS		Yes	Yes
hspace	img, object	CSS
language	script	The type attribute		No
link	body	CSS		Yes
noshade	hr	CSS
nowrap	td, th	CSS
size	basefont, font, hr	CSS
start	ol	None
text	body	CSS
type	li, ul, ol	CSS
version	html	DTD	No	No	No	No	No
vlink	body	CSS	Yes	Yes	Yes	Yes	Yes
width	hr, pre, td, th	CSS
vspace	img, object	CSS

Proprietary HTML elements

Tag	Function	Introduced by	Alternative solution	Trident	Gecko	WebKit	KHTML	Presto
bgsound	Used to add sound to the background of a website	Internet Explorer	audio	<3.1^[IE 3.0]	No	No	No	Dropped[16]
blink	Used to display a blinking text	Netscape	Javascript, CSS	No	Dropped[17]	Yes	No	1.0
bq	Used to display a blockquote	WebTV, HTML 3.0	blockquote	No	No	No	No	Dropped[18]
comment	Used to allow the addition of comments to HTML documents	Internet Explorer, WebTV	<!-- ... -->	3.1	No	No	No	No
ilayer	Inline layers	Netscape (4 only)	iframe	No	No	No	Partial	No
image	Synonym of img	?	img	3.1	Yes	Yes	Yes	Yes
layer	Used to create multiple layers of text and images which lay on top of each other in a given order	Netscape (4 only)	CSS, AJAX	No	No	No	Partial	No
marquee	Used to display a scrolling, marquee-like text.	Internet Explorer, WebTV	JavaScript, CSS3	3.1	1.7	125	3.3	1.0
nobr	Prevents any line breaks from occurring within the flow of a text	Netscape[19][20]	CSS	3.1	Yes	Yes	Yes	Yes
noembed	Displays an alternative text for browsers which do not recognize the embed tag	Netscape	Child elements of object used as fallback
spacer	Adds whitespace in a layout	Netscape	CSS	No	Dropped[21]	No	No	No
wbr	Placed inside a nobr element to add a line break	Netscape[19][20]	Unicode character zero-width space (U+200B)	Dropped[note 3]	1.7	Yes	3.1	No
xml[23]	Delimits an XML data island inside an HTML page	Internet Explorer	?	3.1	No	No	No	No

Proprietary HTML attributes

Attribute	Deprecated for	Function	Supported first by	Trident	Gecko	WebKit	KHTML	Presto
bgproperties	body	Determines whether background image scrolls with the background	Internet Explorer	3.1	No	Yes	Yes	No
bordercolor	body	Sets colors for 3-D table borders in the table, td, th, and tr elements	Internet Explorer		No	Yes	Yes	No
bordercolordark	body	Sets colors for 3-D table borders in the table, td, th, and tr elements	Internet Explorer		No	No	No	No
bordercolorlight	body	Sets colors for 3-D table borders in the table, td, th, and tr elements	Internet Explorer
controls	img	Uses the img element to place video or audio clips	Internet Explorer		No	No	No	No
dynsrc	img	Uses the img element to place video or audio clips	Internet Explorer		No	No	No	No
event	script	Defines function to call for an object.	Internet Explorer		Partial	?	?	?
for	script	Defines the object to bind a scripting event.	Internet Explorer		Partial	?	?	?
frame	table	Controls the display of the outer borders of a table in the table tag	Internet Explorer		Yes	?	Yes	No
framespacing	frameset	Sets the amount of space between frames	Internet Explorer		?	?	No	No
leftmargin	body	Sets the margin between the browser window and the contents of the page	Internet Explorer	3.1	?	?	Yes	No
loop	img	Uses the img element to place video or audio clips	Internet Explorer		No	No	No	No
rightmargin	body	Sets the margin between the browser window and the contents of the page	Internet Explorer	3.1	?	?	No	No
start	img	Uses the img element to place video or audio clips	Internet Explorer		No	No	No	No
target	form	Specifies a target window or frame for the output of a form	Internet Explorer		No[24]	?	Yes	No
valign	caption	Sets vertical alignment of table caption	Internet Explorer	3.1	?	?	No	No

See also

• Web standards
• Wireless Markup Language

Notes

1. Supported for only img.
2. Supported for only font.
3. Trident dropped support for wbr in version 5.0.^[22]

References

1. Amaya Binary Releases, Most recent download link in stable
2. Change log between EdgeHTML 12.10240 and 13.10586
3. "Firefox — Notes (44.0.2) — Mozilla". mozilla.org. 2016-02-11. Retrieved 2016-02-12.
4. "Firefox — Notes (38.6.1) — Mozilla". mozilla.org. 2016-02-11. Retrieved 2016-02-12.
5. "Firefox — Beta Notes (45.0beta) — Mozilla". 2016-01-27. Retrieved 2016-01-29.
6. "Mozilla Firefox Web Browser — Download Firefox Beta in your language — Mozilla". Retrieved 2016-02-17.
7. "Firefox — Aurora Notes (46.0a2) — Mozilla". 2016-01-26. Retrieved 2016-01-29.
8. "RapidRelease/Calendar - MozillaWiki". Retrieved 2016-01-29.
9. Download for kdelibs, Most recent download link in stable
10. Pdfcrowd FAQ, “Pdfcrowd is built around Webkit.”
11. ‘Producer’ metadata in the resulting pdf.
12. HTML 4 Changes, W3C, 18 December 1997, retrieved 2008-05-07
13. Bug 3875 - (basefont) deprecated basefont element not supported, Mozilla
14. HTML 3.2 Reference Specification, W3C, 14 January 1997, retrieved 2008-10-08
15. Isindex Example, retrieved 2008-05-07
16. Tommy A. Olsen (28 November 2011). "Opera Desktop Team - Glyphs and plugins". Retrieved 28 November 2011. CORE-34613 Drop support for <bgsound>
17. "Mozilla Aurora Notes". Mozilla. Retrieved 1 June 2013.
18. gsnedders (9 September 2010). "IRC logs: freenode / #whatwg / 2010-09-09". Retrieved 9 September 2010. # [17:27] <gsnedders> I know we dropped support for the bq element :P
19. "Complete List of HTML Tags". Retrieved 10 October 2011.
20. "Extensions to HTML". Netscape. 1994. Retrieved 10 October 2011.
21. Bug 531056 - [HTML5] Remove spacer support, Mozilla
22. Zeilenumbruch erlauben (in German), Impressum
23. XML Element | xml Object, Microsoft
24. Bug 207900 - psychotekk.de - the target attribute in the form element is ignored, Mozilla

• DevGuru HTML - Non-standard elements at the Wayback Machine (archived 29 January 2013)
• OS/2 Web Explorer's proprietary HTML elements
• MSDN Handling Events with HTML elements