Comparison of layout engines (Non-standard HTML)

{{Html series}}
The following tables compare deprecated and proprietary [[HTML tags]] and [[HTML#Attributes|attributes]] compatibility and support for a number of [[layout engine]]s. Please see the individual products' articles for further information. This article is not all-inclusive or necessarily up-to-date. 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 browser]]s and [[web page]]s were mostly non-existent. Different browsers and [[HTML]] editors were being offered by competing vendors such as [[Netscape]], [[Microsoft]] and [[WebTV]], all of whom possessed their own IDeaS for how web sites should be constructed. These varying standards resulted in web developers coding for specific web browsers, using tags which could often be recognized by only one browser.

{{Explanation of the tables}}
{{Explanation of the tables2}}

==Deprecated HTML tags==
{| class="wikitable" style="text-align: center"
! Tag
! Function
! Supported first by
! Deprecated in W3C HTML Version
! Alternative Solution
! [[Trident (layout engine)|Trident]]
! [[Tasman (layout engine)|Tasman]]
! [[Gecko (layout engine)|Gecko]]
! [[WebKit]]
! [[KHTML]]
! [[Presto (layout engine)|Presto]]
! [[iCab]]
! [[Prince XML]]
|-
| <applet>||Insert an applet||[[HotJava]]
|4 <ref name="deprecated-4.0">{{Citation
| title = HTML 4 Changes
| publisher = [[World Wide Web Consortium|W3C]]
| date = [[1997-12-18]]
| year = 1997
| url = http://www.w3.org/TR/REC-html40/appendix/changes.html#h-A.3.1
| accessdate = 2008-05-07
}}</ref>
|&lt;object&gt;
| {{yes|4.0}}
| {{yes}}
| {{yes|1.7}}
| {{yes}}
| {{yes}}
| {{yes|7.0}}
| {{yes}}
| {{no}}
|-
| &lt;basefont&gt;||sets font styles||Internet Explorer||4||[[CSS]] Styles: font-family, color, font-size
| {{yes|2.0}}
| {{yes}}
| {{no}}[https://bugzilla.mozilla.org/show_bug.cgi?id=basefont]
| {{yes|1.0}}
| {{yes}}
| {{yes}}
| ?
| {{no}}
|-
| &lt;blackface&gt;||Used to display text in a double-weight bold font face||WebTV||----||Alternate fonts<br />CSS Style: font-weight
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
|-
| &lt;center&gt;||centers elements||Netscape<ref name="deprecated-center">{{Citation
| title = HTML 3.2 Reference Specification
| publisher = [[World Wide Web Consortium|W3C]]
| date = [[1997-01-14]]
| year = 1997
| url = http://www.w3.org/TR/REC-html32.html#center
| accessdate = 2008-10-08
}}</ref>||4||CSS Styles: text-align:center (text) <br /> margin-left auto; margin-right: auto; (block elements with set width)
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| ?
| ?
|-
| &lt;dir&gt;||directory list||----||4||&lt;ul&gt;<br />&lt;ol&gt;
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| ?
| ?
|-
| &lt;font&gt;||applies font styles||Netscape||4||CSS Styles: font-family, color, font-size
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| ?
| ?
|-
| &lt;isindex&gt; <ref name="obscure-isindex">{{Citation
| title = Isindex Example
| url = http://obscuretags.com/isindex.html
| accessdate = 2008-05-07
}}</ref>
|adds a search field||----||4||&lt;form&gt;<br />&lt;input type="text"&gt;
| {{yes|5.5}}
| ?
| {{yes|1.7}}
| {{yes|1.3}}
| {{yes}}
| {{partial}}
| ?
| ?
|-
<!-- note for further editing: http://tools.ietf.org/html/rfc1866#section-5.5 this tag is not in the html 2.0 draft, I will change/note this in this week! -->
| &lt;listing&gt;||Succeeded by &lt;pre&gt;...&lt;/pre&gt; tag; displays preformatted text||[[W3C]]||3.2||&lt;samp&gt;<br />&lt;code&gt;<br />&lt;pre&gt;<br />CSS Styles: font-family:[[Monospaced font|monospace]]; <br /> white-space with the value pre, pre-wrap or pre-line
| {{yes|1.0}}
| ?
| {{yes|1.7}}
| {{yes|1.2}}
| {{yes|3.3}}
| {{yes}}
| ?
| ?
|-
| &lt;menu&gt;||menu list||----||4||&lt;ul&gt;<br />&lt;ol&gt;
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| ?
| ?
|-
| &lt;plaintext&gt; || Designates that all HTML tags be ignored, and to display the page as is || ---- || 3.2 || Convert all &lt; characters into HTML entity &amp;lt; and all &gt; characters into HTML entity &amp;gt;.
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| ?
| ?
|-
| &lt;s&gt;||strike through||----||4||&lt;del&gt;<br />CSS Styles: text-decoration:line-through
| {{yes|4.0}}
| {{yes}}
| {{yes|1.7}}
| {{yes}}
| {{yes}}
| {{yes|7.0}}
| {{yes}}
| {{yes|6.0}}
|-
| &lt;shadow&gt;||Adds shadow to text||WebTV||----||CSS 3 Style: text-shadow
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| ?
|-
| &lt;strike&gt;||strike through||----||4||&lt;del&gt;<br />CSS Style: text-decoration:line-through
| {{yes|4.0}}
| {{yes}}
| {{yes|1.7}}
| {{yes}}
| {{yes}}
| {{yes|7.0}}
| {{yes}}
| {{yes|6.0}}
|-
| &lt;u&gt;||underline||----||4||CSS Style: text-decoration:underline
| {{yes|4.0}}
| {{yes}}
| {{yes|1.7}}
| {{yes}}
| {{yes}}
| {{yes|7.0}}
| {{yes}}
| ?
|-
<!-- note for further editing: http://tools.ietf.org/html/rfc1866#section-5.5 this tag is not in the html 2.0 draft, I will change/note this in this week! -->
| &lt;xmp&gt;||Similar to [[PRE]] and [[plaintext (HTML tag)|&lt;plaintext&gt;]], but ignores all HTML tags within and displays as is.||----||3.2||&lt;samp&gt;<br />&lt;code&gt;<br />Convert &lt; characters inside tag into HTML entity &amp;lt; and all &gt; characters into HTML entity &amp;gt;.
| {{yes|1.0}}
| ?
| {{yes|1.7}}
| {{yes|1.2}}
| {{yes|3.3}}
| {{yes|4.0}}
| ?
| ?
|}

==Deprecated HTML attributes==
{| class="wikitable" style="text-align: center"
! Attribute
! Deprecated if used in tag
! Alternative solution
! [[Trident (layout engine)|Trident]]
! [[Tasman (layout engine)|Tasman]]
! [[Gecko (layout engine)|Gecko]]
! [[WebKit]]
! [[KHTML]]
! [[Presto (layout engine)|Presto]]
! [[iCab]]
|-
|align||caption, div, fieldset, h1, h2, h3, h4, h5, h6, hr, img, input, legend, p, object, table||CSS
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| ?
|-
|alink||body||CSS
| {{yes}}
| ?
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| ?
|-
|background||body||CSS
| {{yes}}
| ?
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| ?
|-
|bgcolor||body, table, td, tr, th||CSS
| {{yes}}
| ?
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| ?
|-
|border||img, object||CSS
| {{yes}}
| ?
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| ?
|-
|clear||br||CSS
| {{yes}}
| ?
| ?
| ?
| {{yes}}
| {{yes}}
| ?
|-
|compact||dl, ol, ul||CSS
| {{no}}
| ?
| {{no}}
| ?
| {{yes}}
| {{yes}}
| ?
|-
|color||basefont, font||CSS
| {{yes}}
| ?
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| ?
|-
|height||td, th||CSS
| {{yes}}
| ?
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| ?
|-
|hspace||img, object||CSS
| {{yes}}
| ?
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| ?
|-
|language||script||Attribute type
| {{yes}}
| ?
| {{no}}
| ?
| {{yes}}
| ?
| ?
|-
|link||body||CSS
| {{yes}}
| ?
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| ?
|-
|noshade||hr||CSS
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| ?
|-
|nowrap||td, th||CSS
| {{yes}}
| ?
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| ?
|-
|size||basefont, font, hr||CSS
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| ?
|-
|start||ol||CSS
| {{yes}}
| ?
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| ?
|-
|text||body||CSS
| {{yes}}
| ?
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| ?
|-
|type||li, ul, ol||CSS
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| ?
|-
|value||li||CSS
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| ?
|-
|version||html||DTD declaration
| {{yes}}
| ?
| ?
| ?
| {{no}}
| ?
| ?
|-
|vlink||body||CSS
| {{yes}}
| ?
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| ?
|-
|width||hr, pre, td, th||CSS
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| ?
|-
|vspace||img, object||CSS
| {{yes}}
| ?
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| ?
|}

==Proprietary HTML tags==
{| class="wikitable" style="text-align: center"
! Tag
! Function
! Supported first by
! Alternative solution
! [[Trident (layout engine)|Trident]]
! [[Tasman (layout engine)|Tasman]]
! [[Gecko (layout engine)|Gecko]]
! [[WebKit]]
! [[KHTML]]
! [[Presto (layout engine)|Presto]]
! [[iCab]]
|-
| &lt;animate&gt; || loads a series of images which are then used as a replacement of the [[throbber]] animation.
| [[IBM WebExplorer]]
| {{n/a}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
|-
| &lt;audioscope&gt; || Used to display the audioscope, a graphical display of sound waves
| WebTV
| [[Adobe Flash|Flash]], [[SVG]], Canvas
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
|-
| &lt;bgsound&gt;|| Used to add sound to the background of a website || Internet Explorer || Flash<br>[[HTML5]]
| {{yes|2.0}}
| {{yes}}
| {{no}}{{refun|Firefox-bgsound}}
| {{no}}
| {{no}}
| {{yes|5.12}}
| ?
|-
| [[Blink element|&lt;blink&gt;]] || Used to display a blinking text || [[Netscape]]
| [[Cascading Style Sheets|CSS]] Style: text-decoration
| {{no}}
| {{no}}
| {{yes|1.7}}
| {{no}}
| {{no}}
| {{yes|7.2}}
| ?
|-
| &lt;bq&gt; || Used to display a [[blockquote]] || WebTV, HTML 3.0
| &lt;blockquote&gt;
| {{no}}
| ?
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| ?
|-
| &lt;comment&gt; || Used to allow the addition of comments to HTML documents || Internet Explorer, WebTV
| &lt;!-- ... --&gt;
| {{yes}}
| ?
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| ?
|-
| &lt;embed&gt; || Used to allow the automatic display of a plug-in || Netscape || HTML5<br>&lt;object&gt;
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
|-
| &lt;fn&gt; || Footnotes || WebTV, HTML 3.0
| &lt;a href="#''anchor''"&gt; combined with &lt;element id="''anchor''"&gt; where ''anchor'' is a valid id
| {{no}}
| ?
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| ?
|-
| &lt;ilayer&gt; || Inline layers || Netscape (4 only)
| &lt;iframe&gt;
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{partial}}
| {{no}}
| ?
|-
| &lt;image&gt; || Synonym of &lt;img&gt; || ----
| &lt;img&gt;
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| ?
|-
| &lt;keygen&gt; || Generates a [[public key certificate]] request and its associated private key || Netscape, Opera
| ?
| {{no}}
| ?
| {{yes}}
| {{yes}}
| {{no}}
| {{yes}}
| ?
|-
|[[Layer (HTML tag)|&lt;layer&gt;]] || Used to create multiple layers of text and images which lay on top of each other in a given order || Netscape (4 only)
| CSS Styles: position, z-index <br /> &lt;iframe&gt;, [[Ajax (programming)|AJAX]]
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{partial}}
| {{no}}
| ?
|-
| &lt;limittext&gt; || Used to set the width of the text display || WebTV
| CSS Style: width
| {{no}}
| ?
| ?
| ?
| {{no}}
| {{no}}
| ?
|-
| [[Marquee tag|&lt;marquee&gt;]] || Used to display a scrolling, marquee-like text. || Internet Explorer, WebTV
| Javascript <br> CSS 3 Style: marquee
| {{yes}}
| {{yes}}
| {{yes|1.7}}
| {{yes|1.2}}
| {{yes|3.3}}
| {{yes|7.2}}
| ?
|-
| &lt;multicol&gt; || Used to format and display multiple columns of text and images || Netscape
| CSS 3 Style: columns
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| ?
|-
| [[Nobr|&lt;nobr&gt;]] || Prevents any line breaks from occurring within the flow of a text || ----
| CSS Style: white-space:nowrap <br>or use &amp;nbsp;
| {{yes}}
| ?
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| ?
|-
| &lt;noembed&gt; || Displays an alternative text for browsers which do not recognize the &lt;embed&gt; tag || Netscape
| {{n/a}}
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
|-
| &lt;nolayer&gt; || Displays an alternative text for browsers which do not recognize the <layer&gt; and <ilayer&gt;tag || Netscape
| {{n/a}}
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
|-
| &lt;nosmartquotes&gt; || Prevents regular single '...' and double "..." quotes from automatically being replaced with smart single ‘...’ and smart double “...” quotes || WebTV
| {{n/a}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| ?
|-
| &lt;rt&gt; || Denotes and annotates the pronunciation text used by the &lt;ruby&gt; text || Internet Explorer
| ?
| {{yes}}
| ?
| {{no}}[https://bugzilla.mozilla.org/show_bug.cgi?id=33339]
| ?
| {{no}}
| {{no}}
| ?
|-
| &lt;ruby&gt; || Container for [[ruby character]] notation. Later a [http://www.w3.org/TR/ruby/ W3C recommendation] || Internet Explorer
| ?
| {{yes}}
| ?
| {{no}}[https://bugzilla.mozilla.org/show_bug.cgi?id=33339]
| ?
| {{no}}
| {{no}}
| ?
|-
| &lt;server&gt; || Inserts [[server-side JavaScript]] into an HTML document || [[Netscape Enterprise Server]]
| See [[server-side JavaScript]]
| {{no}}
| ?
| ?
| ?
| {{no}}
| {{no}}
| ?
|-
| &lt;sidebar&gt; || Creates a sidebar window that displays control elements || WebTV
| {{n/a}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
|-
|&lt;spacer&gt; || Adds whitespace between words || Netscape
| CSS Style: padding, margin
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| ?
|-
| &lt;sound&gt;|| Used to add sound to the background of a website || [[Mosaic (web browser)|Mosaic]] || Flash<br>[[HTML5]]
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
|-
| &lt;wbr&gt; || Placed inside a &lt;nobr&gt; element to add a line break || ----
| UTF-8-separator
| {{no|[[#trident wbr|2.0 - 7.0]]}}
| {{yes}}
| {{yes|1.7}}
| {{Yes}}
| {{yes|3.1}}
| {{no}}
| ?
|-
| &lt;xml&gt; || Delimits an XML data island inside an HTML page || Internet Explorer
| ?
| {{yes}}
| {{yes}}
| ?
| ?
| {{no}}
| ?
| ?
|}

===Trident support notes===
* <tt id="trident_wbr">&lt;wbr&gt;</tt> isn't supported for IE5.0 [http://de.selfhtml.org/html/text/zeilenumbruch.htm#erlauben]; The support is removed in [[Internet Explorer 8]].

===Gecko support notes===
* {{note|Firefox-bgsound}} <bgsound> is only supported with the ''Stop Autoplay'' - Extension[https://addons.mozilla.org/firefox/addon/1765]

==Proprietary HTML attributes==
{| class="wikitable" style="text-align: center"
! attribute
! Deprecated if used in tag
! Function
! Supported first by
! [[Trident (layout engine)|Trident]]
! [[Tasman (layout engine)|Tasman]]
! [[Gecko (layout engine)|Gecko]]
! [[WebKit]]
! [[KHTML]]
! [[Presto (layout engine)|Presto]]
! [[iCab]]
|-
|autoactivate||select||viewer selects the list, it is activated automatically||WebTV
| {{no}}
| ?
| ?
| ?
| ?
| {{no}}
| ?
|-
|bgproperties||body||Determines whether background image scrolls with the background||Internet Explorer
| {{yes}}
| ?
| ?
| ?
| {{yes}}
| {{no}}
| ?
|-
|bordercolor||body||Sets colors for 3-D table borders in the table, td, th, and tr tags||Internet Explorer
| {{yes}}
| ?
| ?
| ?
| {{yes}}
| {{no}}
| ?
|-
|bordercolordark||body||Sets colors for 3-D table borders in the table, td, th, and tr tags||Internet Explorer
| {{yes}}
| ?
| ?
| ?
| {{no}}
| {{no}}
| ?
|-
|bordercolorlight||body||Sets colors for 3-D table borders in the table, td, th, and tr tags||Internet Explorer
| {{yes}}
| ?
| ?
| ?
| {{no}}
| {{no}}
| ?
|-
|controls||img||Uses the image tag to place video or audio clips||Internet Explorer
| {{yes}}
| ?
| ?
| ?
| {{no}}
| {{no}}
| ?
|-
|dynsrc||img||Uses the image tag to place video or audio clips||Internet Explorer
| {{yes}}
| ?
| ?
| ?
| {{no}}
| {{no}}
| ?
|-
|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
| {{yes}}
| ?
| ?
| ?
| {{no}}
| {{no}}
| ?
|-
|ibmlogo||img||used to show some internal mini images||IBM WebExplorer
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
|-
|internal-gopher-menu||img||used to show some internal mini images||IBM WebExplorer
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
|-
|left_arrow||img||used to show some internal mini images||IBM WebExplorer
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
|-
|leftmargin||body||Sets the margin between The Browser window and the contents of the page||Internet Explorer
| {{yes}}
| ?
| ?
| ?
| {{yes}}
| {{no}}
| ?
|-
|loop||img||Uses the image tag to place video or audio clips||Internet Explorer
| {{yes}}
| ?
| ?
| ?
| {{no}}
| {{no}}
| ?
|-
|red_bullet||img||used to show some internal mini images||IBM WebExplorer
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
|-
|rightmargin||body||Sets the margin between the browser window and the contents of the page||Internet Explorer
| {{yes}}
| ?
| ?
| ?
| {{no}}
| {{no}}
| ?
|-
|start||img||Uses the image tag to place video or audio clips||Internet Explorer
| {{yes}}
| ?
| ?
| ?
| {{no}}
| {{no}}
| ?
|-
|target||form||Specifies a target window or frame for the output of a form||Internet Explorer
| {{yes}}
| ?
| {{no}}[https://bugzilla.mozilla.org/show_bug.cgi?id=207900]
| ?
| {{yes}}
| {{no}}
| ?
|-
|usestyle||caption||???||WebTV
| {{no}}
| ?
| ?
| ?
| {{no}}
| {{no}}
| ?
|-
|valign||input||Sets vertical alignment of table caption||Internet Explorer
| {{yes}}
| ?
| ?
| ?
| {{no}}
| {{no}}
| ?
|}

==References==
{{Reflist}}
{{Refbegin}}
* [http://www.devguru.com/technologies/html/quickref/html_other_tags.html DevGuru HTML - Non-standard tags]
* [http://www.seds.org/~spider/os2/webextag.html OS/2 Web Explorer's proprietary html tags]
{{Refend}}

==See also==
* [[Web standards]]

{{Layout engines}}

[[Category:HTML]]
[[Category:Layout engines|*]]
[[Category:Software comparisons|Layout engines]]