HTML stands for “HyperText Markup Language”, the markup language for Web pages. HTML file is written in the form of tags. Web page files have .html or .htm filename extensions.
Anchor (most commonly a link)
Use to create links in content. Use the title attribute whenever the contents of the <a>…</a> pair do not accurately describe what you’ll get from selecting the link. Title attribute often displays as a tooltip in visual browsers, which may be a helpful usability aid.
Defines an abbreviation. Works in a similar way to <dfn> and <acronym>, using a title attribute (displays a tooltip in standard visual browsers). e.g. <abbr title=”Hypertext markup language”>HTML</abbr>
Defines an acronym. Works in a similar way to <abbr> and <dfn>, using a title attribute (displays a tooltip in standard visual browsers).
Used for marking up a physical (e.g. mailing) address. Not commonly used. Recommend looking into microformats, which allow for more detail and interoperability.
Inserts a Java applet. The old way to insert a Java app. Use <object> instead today.
Hotspot in image map. Avoid image maps where possible. Occasionally necessary.
Specifies the base location of the document. Use only when necessary. Adjusts any relative links and paths within the document.
Sets default font size
Makes text blink.
Large quoted block of text. Use for any quoted text that constitutes one or more paragraphs (note: should contain <p> tags as well). Use <q> for quotations within a paragraph. Often used in conjunction with <cite> to cite the quotation’s source.
Document body. Essential (unless you’re using frames)
Line break. This is arguably display information. Still in common use, but use with restraint.
Bold text. Display info – never use it
Used for a standard clickable button within a form. Often better than <input type=”button” /> or <input type=”submit” />, as it allows you to assign different styles based on the HTML element alone, whereas differentiating style based on the type of input is less well supported.
Caption for a table: describes the table’s contents. The correct way to assign a title to a table
Centred block. Display info – never use it. Use <div> or some other block-level tag with the style text-align:center instead
Defines a citation. Defines the source of a quotation (in conjunction with content in <q> or <blockquote> pairs).
Defines an extract of code. Not commonly used. Similar to <pre> tag, but collapses consecutive white spaces and line breaks in the source.
Identifies a particular column in a table Can be very useful. e.g. <col class=”namecol”> can be applied to each first column in a series of tables, then the width of each column may be set to be equal in the stylesheet, overriding the table’s natural tendency to adjust its own column widths to fit its contents.
Definition of a term. Works in a similar way to <abbr> and <acronym>, using a title attribute (displays a tooltip in standard visual browsers).
Directory list now deprecated. Use a standard <ul> or other list instead.
Division – Specifies a logical division within a document. Use it to separate or identify chunks of content that are not otherwise distinguished naturally using other tags.
One of the most common HTML tags.
Definition list contains one or more definition-term / definition-description pairs.
Definition term Used as part of a <dt> </dt> <dd> </dd> pair within a definition list (<dl></dl>)
Emphasis Commonly used in place of the old <i> (italics) tag to indicate emphasis (but less than <strong>)
Level 1 header . Aim to have one H1 on each page, containing a description of what the page is about.
Level 2 header. Defines a section of the page
Level 3 header. Defines a sub-section of the page (should always follow an H2 in the logical hierarchy)
Level 4 header. Less commonly used
Level 5 header. Less commonly used. Only complex academic documents will break down to this level of detail.
Level 6 header.
Document head . Contains information about a page that does not constitute content to be communicated as part of the page.
Horizontal rule Display info with no semantic value – never use it. “Horizontal”, by definition, is a visual attribute.
Core element of every web page.
Show an image. Always use the alt or long description attributes when the image has content value
Input fields within forms are Vital. Prefer to use <button> for buttons and submit buttons though)
Old type of search input. Not really used any more. Use <form> instead.
Defines a relationship to another document. Commonly used to reference external stylesheets, but has other minor uses
List item . Specifies an item in an unordered or ordered list (<ul> or <ol>)
Client-side imagemap May have occasional value, but only use when absolutely necessary
Makes text scroll across the screen
Menu item list Deprecated. Do not use. Use other standard list types instead.
Meta-information – Useful way to insert relevant information into the <head> section of the page that does not need to be displayed.
Ordered list – Type of list where the order of elements has some meaning. Generally rendered with item numbers (best managed with CSS).
Selection list option – Vital for options within a drop-down control.
Parameter for Java applet. Used in conjunction with an <object> or <applet> tag to pass additional setting information at runtime.
Preformatted text – Renders text in a pre-formatted style, preserving line breaks and all spaces present in the source. May be useful. (This one’s a paradox, as it is strictly display info that applies only to visual browsing, but it’s still so commonly used and useful that I’m hesitant to advise against using it.)
Paragraph – Only use to denote a paragraph of text. Never use for spacing alone.
Short quotation – Use for inline quotations (whereas <blockquote> should be used for quotations of a paragraph or more). Often used in conjunction with <cite> to cite the quotation’s source.
Denotes sample output text. Similar to the <code> tag.
Selection list – A drop-down selector for a form.
Smaller text – Display info – never use it
An inline span within text – Use to apply meaning (and style) to a span of text that goes with the flow of content (whereas a <div> tag is block-level and breaks the flow)
Display info – never use it
Strong emphasis – Use this instead of the old <b> tag.
CSS style settings – Normally used in <head> section of a page. Try to use external stylesheets, to enable you to apply different styles for different output media.
Subscript text – Arguably display info – recommend using alternative tags (e.g. <cite>). May be required in some academic uses, e.g. Chemical formulas.
Table – Use for repeated data that has a naturally tabular form. Never use for layout purposes.
Table data cell – A cell containing actual data. If a cell actually contains a descriptor or identifier for a row or column, use a <th> (table header) tag, not a <td>. This usually applies to column headers (within a <thead>), column footers (within a <tfoot>), as well as row headers (usually the first cell in a row in the <tbody>).
Multi-line text input area in a form
Table column or row header cell. May appear in a <thead> (to denote a column header cell), <tbody> (to denote a row header), and in <tfoot> (to denote a column foot cell, e.g. a total)