[whatwg] microdata: itemprop in <col> tag

[David Karger]

One natural way to represent a collection of structured items is in an 
html table.  this can coexist with microdata, by using <tr itemscope> 
and <td itemprop> tags.  But by ignoring the structure of the table, 
this creates a lot of redundant attribute specification.

It would yield cleaner markup if it were possible to use <col 
itemprop="foo"> to indicate an item property that should be inherited by 
all cells in the given column.  In other words, to assert that any <td> 
associated with a <col> should inherit the itemprop associated with that 
<col> .

It would yield even cleaner markup if there were a way to indicate that 
every <tr> was a distinct itemscope (the common case).  For example, to 
use <table itemtype="bar"> to indicate that each row of the table scopes 
an item of type bar.    Or perhaps <table itemscope> could be 
interpreted as asserting a distinct itemscope for each row without 
specifying a type.

But even using just the <col> inheritance rule, while still placing 
itemscope in <tr> tags, would save a quadratic quantity of markup.