Bug 285415 – colspan=0 and rowspan=0 do not behave the same way for rendering in all browsers

• Component: Tables
• Status: NEW

[Karl Dubost]

This is not really a bug on WebKit as this is happening on all browsers. It is more a rendering difference in between colspan and rowspan.

<b>simple table width border=1 / colspan=0</b>
<table border="1">
  <tr><td colspan="0">A1</td></tr>
  <tr><td>B1</td><td>B2</td><td>B3</td></tr>
  <tr><td>C1</td><td>C2</td><td>C3</td></tr>
</table>

The cell rendering of A1 doesn't spread on all cells like it would do for colspan=3


rowspan=0 creates a joint space in both firefox/chrome (and in webkit after https://github.com/WebKit/WebKit/pull/38398) which is identical to a rowspan=n for a table of n rows.

On the other hand, colspan=0 is weird. It creates a square cell but doesn't really span it, it just removes the space remaining.

To see the difference of behavior in Safari, we need to wait the landing of Bug 185341

[Karl Dubost]

Created attachment 473792 [details]
rendering in safari, firefox, chrome

Probably more visible with this test. 
https://codepen.io/webcompat/pen/EaYoPWb

we can see than 
1. in the case of rowspan, the A letters are distributed for the full height of the table, 
2. while in the case of the colspan it is not using the full width of the table. 

Again the current rendering on Safari is wrong because of Bug 185341

[Karl Dubost]

Created attachment 473793 [details]
rendering in safari, firefox, chrome

Added a colspan=3 to show how it should behave. 
Probably WPT tests are needed, depending on what we think is the right behavior.

[Radar WebKit Bug Importer]

<rdar://problem/142800079>