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Detailed explanation of the use and function of tag in html
- 黄舟Original
- 2017-06-21 13:35:594185browse
The
dir attribute in the html tag can be regarded as an international attribute. The dir attribute can be used to specify the display direction of text in the browser.
When you need to specify the directionality of the entire document or most of the document, you should use the dir attribute in the 100db36a723c770d327fc0aef2ce13b1 element instead of using this attribute in the 6c04bd5ca3fcae76e30b72ad730ca86d element. There are two reasons. : The 100db36a723c770d327fc0aef2ce13b1 element is better supported by browsers, and the attribute is then applied to the head element as well as elements in the body. If you wish to change the orientation of a small portion of the document, you can also use the dir attribute on an element in the body of the document. The
dir attribute has two values:
ltr: left to right, default value.
rtl: From right to left, some languages, such as Hebrew or Arabic, or ancient Chinese classical Chinese, are read from right to left.
Usage examples are as follows:
Define documents that are read from left to right:
<html dir="ltr">
Define documents that are read from right to left:
<html dir="rtl">
Let’s first Let’s look at a simple example:
<bdo dir="ltr">我非常爱你</bdo> <bdo dir="rtl">你爱常非我</bdo>
You will understand the effect by putting the above code into HTML;
Note: The bod tag must be used together. The dir tag attribute, ltr refers to the arrangement order from left to right, and rtl refers to the arrangement order from right to left.
The display result is:
我非常爱你 我非常爱你
We see that different text sorting becomes the same display result after being defined by bdo. This is the role of bdo. The Unicode bidirectional algorithm automatically reverses the embedded character sequence based on its directional properties. For example, the basic direction of English documents is left to right (ltr). If a section of the document contains language that reads from right to left (rtl), you can apply a bidirectional algorithm to reverse the direction of the language. The bidirectional algorithm and the DIR tag attribute are usually sufficient to handle changes in embedding orientation. However, when you submit formatted text to a bidirectional algorithm, errors may occur. For example, a text segment containing English and Hebrew formatted in an email will be incorrectly converted by the bidirectional algorithm. Since the reading order of the Hebrew text has already been converted in email format, applying the bidirectional algorithm to it causes the text to be converted again. The bdo element will turn off the bidirectional algorithm and control the reading order. When you use the bdo element you must use the dir tag attribute.
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