How to assign a width to parent (!) of <img> element?

[pstein]

Assume I have the following simplified code
 

<div>

<img class="dummy">....</img>

</div>

Ok, I can now assign a new width (overwrite) to the <img> element by entering

img.dummy { width: 50% !important; }

But what if I want to assign the width to its parent element (here the <div>)?

How can I assign an attribute+value to this unknown element (without ID or class)?

Keep in mind I have no access to the original webpage+CSS source but want to assign it later from script.

 

[Ingolme]

CSS only selects downwards and forwards so that the rendering engine only needs to do a single pass through the HTML document.

What you have to do is find the closest ancestor with a class or ID and reach the div through a series of child and element selectors. The resulting selector might look something like this:

.something > section:nth-child(2) > div:nth-child(4)