Basics
For controlling "cellpadding" in CSS, you can simply use padding on table cells. E.g. for 10px of "cellpadding":
td {
padding: 10px;
}
For "cellspacing", you can apply the border-spacing CSS property to your table. E.g. for 10px of "cellspacing":
table {
border-spacing: 10px;
border-collapse: separate;
}
This property will even allow separate horizontal and vertical spacing, something you couldn't do with old-school "cellspacing".
Issues in IE ≤ 7
This will work in almost all popular browsers except for Internet Explorer up through Internet Explorer 7, where you're almost out of luck. I say "almost" because these browsers still support the border-collapse property, which merges the borders of adjoining table cells. If you're trying to eliminate cellspacing (that is, cellspacing="0") then border-collapse:collapse should have the same effect: no space between table cells. This support is buggy, though, as it does not override an existing cellspacing HTML attribute on the table element.
In short: for non-Internet Explorer 5-7 browsers, border-spacing handles you. For Internet Explorer, if your situation is just right (you want 0 cellspacing and your table doesn't have it defined already), you can use border-collapse:collapse.
table {
border-spacing: 0;
border-collapse: collapse;
}
Note: For a great overview of CSS properties that one can apply to tables and for which browsers, see this fantastic Quirksmode page.
There is currently no way to select the parent of an element in CSS.
If there was a way to do it, it would be in either of the current CSS selectors specs:
That said, the Selectors Level 4 Working Draft includes a :has() pseudo-class that will provide this capability. It will be similar to the jQuery implementation.
li:has(> a.active) { /* styles to apply to the li tag */ }
However, as of 2021, this is still not supported by any browser.
In the meantime, you'll have to resort to JavaScript if you need to select a parent element.
Best Answer
Yes, it is a good technique.
You can reduce the number of HTTP requests and it is a page optimization technique.
The first rule in
Best Practices for Speeding Websites by Yahoo
is
Minimize HTTP Requests
When you need to change the dimensions of the images inside the sprite then you have to recalculate the offsets for the images. But I don't think this is a huge burden.
It is supported by almost all modern browsers.
This is also a good article on CSS sprites
CSS Sprites: What They Are, Why They’re Cool, and How To Use Them