tab-stops 特性 (CSS)p Tab Stops
Tab stops are not a feature provided by [CSS2] or the [XHTML] specification, however, the following extensions are provided for setting tab-stops at either a repeating interval or at specific locations. For compatibility with [XHTML], tabs are invoked using an element with a style attribute. The ASCII tab character (U0009) is ordinary white space that does not advance to the next tab-stop.
Default tab stops may be set at a repeating interval via the use of a nonstandard [CSS2] style attribute tab-interval. The default tab stops occur at every multiple of the specified measurement value. However, these tab stops are in effect only beyond the positions specified by the nonstandard [CSS2] style attribute tab-stops described below. As a consequence, if no tab stops were defined with the tab stops attribute then all of the default tab stop positions will be in effect.
Default tab stops are always left tabs, that is, after advancing to the tab stop subsequent text is left-aligned with the tab stop.
This attribute is defined as:
tab-interval:sizewhere size is a non-zero measurement
A span element with a style attribute of xfa-tab-count may be used to advance by a specific number of tab-stops relative to the current position. The span element is recommended to be empty, as any text or markup that is contained within the span may be discarded by an XFA processing application.
xfa-tab-count:countwhere count is a non-negative integer representing the number of tabs-stops to advance When count is zero the xfa-tab-count attribute must have no effect.
Example:
<p style="tab-interval:0.5in">A <span style="xfa-tab-count:2" />B <span style="xfa-tab-count:1" />C</p>Produces:
A B CTab-stops may be set at specific locations via the use of a nonstandard [CSS2] style attribute tab-stops.
This attribute is defined as:
tab-stops:align measurement[ align measurement]...Note: This document uses the monospaced italics type face to indicate placeholders. In actual use, meaningful values replace such placeholders.
align values are described in the following table.
align value Effect center Center-aligned tab stop left Left-aligned tab stop right Right-aligned tab stop decimal Tab-stop that aligns content around a radix point A center-aligned tab stop causes the text following the tab to be centered on the tab stop position. A left-aligned tab stop causes the text following the tab to be left-aligned with the tab stop position. A right-aligned tab stop causes the text following the tab to be right-aligned with the tab stop position. A radix-aligned tab stop is used with numeric data. It causes the text following the tab to be aligned with its radix character (for example, in English-speaking locales) left-aligned with the tab stop position. If the text has no radix character the text is right-aligned with the tab stop position. The determination of the appropriate radix character for the locale is implementation-defined.
The cursor position starts at the left margin and the tab index starts at zero upon entry to the element that declares the tab-stops. Within a p element that declares tab-stops, a br element restarts the cursor position at the left margin and the tab index at zero.
Example:
<p style="tab-stops:left 0.5in left 2in"> <span style="xfa-tab-count:1" />Charles <span style="xfa-tab-count:1" />Porter<br /> <span style="xfa-tab-count:1" />Alice <span style="xfa-tab-count:1" />Crawford </p>Produces:
Charles Porter Alice CrawfordExample:
<p style="font-family:courier;tab-stops:decimal 0.5in"> <span style="xfa-tab-count:1" />1.2345<br /> <span style="xfa-tab-count:1" />99<br /> <span style="xfa-tab-count:1" />-.033<br /> <span style="xfa-tab-count:1" />$ 17.60 plus tax </p>Produces:
1.2345 99 -.033 $ 17.70 plus tax
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