Alignment, Font Styles, And Horizontal Rules In HTML Documents

Trang chủ » Html Td Style Align Center » Alignment, Font Styles, And Horizontal Rules In HTML Documents

Có thể bạn quan tâm

previous next contents elements attributes index 15 Alignment, font styles, and horizontal rules

Contents

  1. Formatting
    1. Background color
    2. Alignment
    3. Floating objects
      • Float an object
      • Float text around an object
  2. Fonts
    1. Font style elements: the TT, I, B, BIG, SMALL, STRIKE, S, and U elements
    2. Font modifier elements: FONT and BASEFONT
  3. Rules: the HR element

This section of the specification discusses some HTML elements and attributes that may be used for visual formatting of elements. Many of them are deprecated.

15.1 Formatting

15.1.1 Background color

Attribute definitions

bgcolor = color [CI] Deprecated. This attribute sets the background color for the document body or table cells.

This attribute sets the background color of the canvas for the document body (the BODY element) or for tables (the TABLE, TR, TH, and TD elements). Additional attributes for specifying text color can be used with the BODY element.

This attribute has been deprecated in favor of style sheets for specifying background color information.

15.1.2 Alignment

It is possible to align block elements (tables, images, objects, paragraphs, etc.) on the canvas with the align attribute. Although this attribute may be set for many HTML elements, its range of possible values sometimes differs from element to element. Here we only discuss the meaning of the align attribute for text.

Attribute definitions

align = left|center|right|justify [CI] Deprecated. This attribute specifies the horizontal alignment of its element with respect to the surrounding context. Possible values:
  • left: text lines are rendered flush left.
  • center: text lines are centered.
  • right: text lines are rendered flush right.
  • justify: text lines are justified to both margins.

The default depends on the base text direction. For left to right text, the default is align=left, while for right to left text, the default is align=right.

DEPRECATED EXAMPLE: This example centers a heading on the canvas.

<H1 align="center"> How to Carve Wood </H1>

Using CSS, for example, you could achieve the same effect as follows:

<HEAD> <TITLE>How to Carve Wood</TITLE> <STYLE type="text/css"> H1 { text-align: center} </STYLE> <BODY> <H1> How to Carve Wood </H1>

Note that this would center all H1 declarations. You could reduce the scope of the style by setting the class attribute on the element:

<HEAD> <TITLE>How to Carve Wood</TITLE> <STYLE type="text/css"> H1.wood {text-align: center} </STYLE> <BODY> <H1 class="wood"> How to Carve Wood </H1>

DEPRECATED EXAMPLE: Similarly, to right align a paragraph on the canvas with HTML's align attribute you could have:

<P align="right">...Lots of paragraph text...

which, with CSS, would be:

<HEAD> <TITLE>How to Carve Wood</TITLE> <STYLE type="text/css"> P.mypar {text-align: right} </STYLE> <BODY> <P class="mypar">...Lots of paragraph text...

DEPRECATED EXAMPLE: To right align a series of paragraphs, group them with the DIV element:

<DIV align="right"> <P>...text in first paragraph... <P>...text in second paragraph... <P>...text in third paragraph... </DIV>

With CSS, the text-align property is inherited from the parent element, you can therefore use:

<HEAD> <TITLE>How to Carve Wood</TITLE> <STYLE type="text/css"> DIV.mypars {text-align: right} </STYLE> <BODY> <DIV class="mypars"> <P>...text in first paragraph... <P>...text in second paragraph... <P>...text in third paragraph... </DIV>

To center the entire document with CSS:

<HEAD> <TITLE>How to Carve Wood</TITLE> <STYLE type="text/css"> BODY {text-align: center} </STYLE> <BODY> ...the body is centered... </BODY>

The CENTER element is exactly equivalent to specifying the DIV element with the align attribute set to "center". The CENTER element is deprecated.

15.1.3 Floating objects

Images and objects may appear directly "in-line" or may be floated to one side of the page, temporarily altering the margins of text that may flow on either side of the object.

Float an object

The align attribute for objects, images, tables, frames, etc., causes the object to float to the left or right margin. Floating objects generally begin a new line. This attribute takes the following values:

  • left: Floats the object to the current left margin. Subsequent text flows along the image's right side.
  • right: Floats the object to the current right margin. Subsequent text flows along the image's left side.

DEPRECATED EXAMPLE: The following example shows how to float an IMG element to the current left margin of the canvas.

<IMG align="left" src="http://foo.com/animage.gif" alt="my boat">

Some alignment attributes also permit the "center" value, which does not cause floating, but centers the object within the current margins. However, for P and DIV, the value "center" causes the contents of the element to be centered.

Float text around an object

Another attribute, defined for the BR element, controls text flow around floating objects.

Attribute definitions

clear = none|left|right|all [CI] Deprecated. Specifies where the next line should appear in a visual browser after the line break caused by this element. This attribute takes into account floating objects (images, tables, etc.). Possible values:
  • none: The next line will begin normally. This is the default value.
  • left: The next line will begin at nearest line below any floating objects on the left-hand margin.
  • right: The next line will begin at nearest line below any floating objects on the right-hand margin.
  • all: The next line will begin at nearest line below any floating objects on either margin.

Consider the following visual scenario, where text flows to the right of an image until a line is broken by a BR:

********* ------- | | ------- | image | --<BR> | | *********

If the clear attribute is set to none, the line following BR will begin immediately below it at the right margin of the image:

********* ------- | | ------- | image | --<BR> | | ------ *********

DEPRECATED EXAMPLE: If the clear attribute is set to left or all, the next line will appear as follows:

********* ------- | | ------- | image | --<BR clear="left"> | | ********* -----------------

Using style sheets, you could specify that all line breaks should behave this way for objects (images, tables, etc.) floating against the left margin. With CSS, you could achieve this as follows:

<STYLE type="text/css"> BR { clear: left } </STYLE>

To specify this behavior for a specific instance of the BR element, you could combine style information and the id attribute:

<HEAD> ... <STYLE type="text/css"> BR#mybr { clear: left } </STYLE> </HEAD> <BODY> <P>... ********* ------- | | ------- | table | --<BR id="mybr"> | | ********* ----------------- ... </BODY>

15.2 Fonts

The following HTML elements specify font information. Although they are not all deprecated, their use is discouraged in favor of style sheets.

15.2.1 Font style elements: the TT, I, B, BIG, SMALL, STRIKE, S, and U elements

<!ENTITY % fontstyle "TT | I | B | BIG | SMALL"> <!ELEMENT (%fontstyle;|%phrase;) - - (%inline;)*> <!ATTLIST (%fontstyle;|%phrase;) %attrs; -- %coreattrs, %i18n, %events -- >

Start tag: required, End tag: required

Attributes defined elsewhere

  • id, class (document-wide identifiers)
  • lang (language information), dir (text direction)
  • title (element title)
  • style (inline style information)
  • onclick, ondblclick, onmousedown, onmouseup, onmouseover, onmousemove, onmouseout, onkeypress, onkeydown onkeyup (intrinsic events)

Rendering of font style elements depends on the user agent. The following is an informative description only.

TT: Renders as teletype or monospaced text. I: Renders as italic text style. B: Renders as bold text style. BIG: Renders text in a "large" font. SMALL: Renders text in a "small" font. STRIKE and S: Deprecated. Render strike-through style text. U: Deprecated. Renders underlined text.

The following sentence shows several types of text:

<P><b>bold</b>, <i>italic</i>, <b><i>bold italic</i></b>, <tt>teletype text</tt>, and <big>big</big> and <small>small</small> text.

These words might be rendered as follows:

An example of rendering of various font styles

It is possible to achieve a much richer variety of font effects using style sheets. To specify blue, italic text in a paragraph with CSS:

<HEAD> <STYLE type="text/css"> P#mypar {font-style: italic; color: blue} </STYLE> </HEAD> <P id="mypar">...Lots of blue italic text...

Font style elements must be properly nested. Rendering of nested font style elements depends on the user agent.

15.2.2 Font modifier elements: FONT and BASEFONT

FONT and BASEFONT are deprecated.

See the Transitional DTD for the formal definition.

Attribute definitions

size = cdata [CN] Deprecated. This attribute sets the size of the font. Possible values:
  • An integer between 1 and 7. This sets the font to some fixed size, whose rendering depends on the user agent. Not all user agents may render all seven sizes.
  • A relative increase in font size. The value "+1" means one size larger. The value "-3" means three sizes smaller. All sizes belong to the scale of 1 to 7.
color = color [CI] Deprecated. This attribute sets the text color. face = cdata [CI] Deprecated. This attribute defines a comma-separated list of font names the user agent should search for in order of preference.

Attributes defined elsewhere

  • id, class (document-wide identifiers)
  • lang (language information), dir (text direction)
  • title (element title)
  • style (inline style information)

The FONT element changes the font size and color for text in its contents.

The BASEFONT element sets the base font size (using the size attribute). Font size changes achieved with FONT are relative to the base font size set by BASEFONT. If BASEFONT is not used, the default base font size is 3.

DEPRECATED EXAMPLE: The following example will show the difference between the seven font sizes available with FONT:

<P><font size=1>size=1</font> <font size=2>size=2</font> <font size=3>size=3</font> <font size=4>size=4</font> <font size=5>size=5</font> <font size=6>size=6</font> <font size=7>size=7</font>

This might be rendered as:

Example of rendering of various font sizes

The following shows an example of the effect of relative font sizes using a base font size of 3:

Example of rendering of various font sizes with a basefont

The base font size does not apply to headings, except where these are modified using the FONT element with a relative font size change.

15.3 Rules: the HR element

<!ELEMENT HR - O EMPTY -- horizontal rule --> <!ATTLIST HR %attrs; -- %coreattrs, %i18n, %events -- >

Start tag: required, End tag: forbidden

Attribute definitions

align = left|center|right [CI] Deprecated. This attribute specifies the horizontal alignment of the rule with respect to the surrounding context. Possible values:
  • left: the rule is rendered flush left.
  • center: the rule is centered.
  • right: the rule is rendered flush right.

The default is align=center.

noshade [CI] Deprecated. When set, this boolean attribute requests that the user agent render the rule in a solid color rather than as the traditional two-color "groove". size = pixels [CI] Deprecated. This attribute specifies the height of the rule. The default value for this attribute depends on the user agent. width = length [CI] Deprecated. This attribute specifies the width of the rule. The default width is 100%, i.e., the rule extends across the entire canvas.

Attributes defined elsewhere

  • id, class (document-wide identifiers)
  • lang (language information), dir (text direction)
  • title (element title)
  • style (inline style information)
  • onclick, ondblclick, onmousedown, onmouseup, onmouseover, onmousemove, onmouseout, onkeypress, onkeydown, onkeyup (intrinsic events)

The HR element causes a horizontal rule to be rendered by visual user agents.

The amount of vertical space inserted between a rule and the content that surrounds it depends on the user agent.

DEPRECATED EXAMPLE: This example centers the rules, sizing them to half the available width between the margins. The top rule has the default thickness while the bottom two are set to 5 pixels. The bottom rule should be rendered in a solid color without shading:

<HR width="50%" align="center"> <HR size="5" width="50%" align="center"> <HR noshade size="5" width="50%" align="center">

These rules might be rendered as follows:

Example of rendering of various horizontal rules

previous next contents elements attributes index

Từ khóa » Html Td Style Align Center