元素:您表示此单元格不是数据但某种标题.通常，此类单元格会在 <thead> 部分中的一行或多行中组合在一起，或者成为每行中的第一个单元格，具体取决于表格的结构和性质.is it necessary to have <th> in any table? even if table has no heading?
table has 3 other tag <thead> <tbody> <tfoot> is it necessary to use all even if i have nothing for table footer. Firefox by default add all these in code.
and is it necessary , <th> always should be in a <thead>
and if I have a heading in content received from client , and heading is from outside the table but related to table then how should i place that heading for table
As a above table <h3>Heading of table<h3>
<table>......</table>
as a heading of table <table>
<thead><tr rowspan=3><th>Heading of table</th></tr></thead>
or as a caption of table <table>
<caption> Heading of table</caption>
Which is good for screen reader and semantically correct? 解决方案 According to the HTML DTD this is the content model for HTML tables:
<!ELEMENT TABLE - -
(CAPTION?, (COL*|COLGROUP*), THEAD?, TFOOT?, TBODY+)>
<!ELEMENT CAPTION - - (%inline;)* -- table caption -->
<!ELEMENT THEAD - O (TR)+ -- table header -->
<!ELEMENT TFOOT - O (TR)+ -- table footer -->
<!ELEMENT TBODY O O (TR)+ -- table body -->
<!ELEMENT COLGROUP - O (COL)* -- table column group -->
<!ELEMENT COL - O EMPTY -- table column -->
<!ELEMENT TR - O (TH|TD)+ -- table row -->
<!ELEMENT (TH|TD) - O (%flow;)* -- table header cell, table data cell-->
So this is illegal syntax: <thead><th>Heading of table</th></thead>
It should be: <thead><tr><th>Heading of table</th></tr></thead>
<th> elements aren't required anywhere. They're simply one of the two cell types (the other being <td>) that you can use in a table row. A <thead> is an optional table section that can contain one or more rows.
Edit: As to why to use <thead> there are several reasons:
- Semantic: You're differentiating between the content of your table and "metadata". This is most often used to delineate between column headers and data rows;
- Accessibility: it helps people who use screen readers to understand the contents of the table;
- Non-Screen Media: Printing a multi-page table may allow you to put the
<thead> contents at the top of each page so people can understand what the columns meaning without flicking back several pages;
- Styling: CSS can be applied to
<tbody> elements, <thead> elements, both or some other combination. It gives you something else to write a selector against;
- Javascript: this often comes up when using jQuery and similar libraries. The extra information is helpful in writing code.
As an example of (5) you might do this: $("table > tbody > tr:nth-child(odd)").addClass("odd");
The <thead> element means those rows won't be styled that way. Or you might do: $("table > tbody > tr").hover(function() {
$(this).addClass("hover");
}, function() {
$(this).removeClass("hover");
});
with: tr.hover { background: yellow; }
which again excludes the <thead> rows.
Lastly, many of these same arguments apply to using <th> elements over <td> elements: you're indicating that this cell isn't data but a header of some kind. Often such cells will be grouped together in one or more rows in the <thead> section or be the first cell in each row depending on the structure and nature of your table.
这篇关于是否有必要拥有<th>在任何表?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
查看全文
| 
