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The “contains” substring matching attribute selector targets an element containing the piece of code we define anywhere in an attribute's value.
Quick Reference
Using substring matching attribute selectors
-
^tells the browser to match a piece of code that’s at the beginning of an attribute's value -
$matches a piece at the end of an attribute's value -
*matches any part of an attribute's value
This selector matches an a element containing the word blog anywhere inside its href value:
a[href*="blog"] {
border-bottom: solid 2px steelblue;
}
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The third substring matching attribute
selector we'll cover is referred to as
0:00
the contains selector and it's called
that, because it targets an element whose
0:04
attribute value contains the piece of code
we define anywhere in the value.
0:08
And I'll show you what I mean.
0:13
So earlier, we used the begins with
selector to give
0:14
links beginning with http.
0:18
A background-repeat, background-size, and
padding-left property.
0:21
While it does the job as we can see we
used it to help define these file type
0:26
icons, I'd prefer a selector that's a bit
more specific and predictable.
0:32
So, let's instead match a link that
contains the word
0:37
downloads anywhere inside the href
attribute value.
0:42
So we'll go back to our style sheet and at
the bottom,
0:46
let's create our new contains selector by
once again targeting an anchor element.
0:49
Then inside the square brackets, we're
gonna target the href attribute.
0:55
And we're going to use the asterisk
character to
1:00
tell the browser that we're selecting
every anchor element who's href
1:04
attribute contains the word downloads
anywhere in the value.
1:08
[BLANK_AUDIO]
1:13
So in this selector, the asterisk is what
defines the contains selector.
1:18
Because, again, it tells the browser to
match a value string that
1:23
contains downloads anywhere in the value
and it doesn't matter if there
1:27
are spaces before or after the substring,
the browser will still match it.
1:32
So let's scroll back up to our first
begins with selector rule, and
1:37
let's keep the color and text decoration
properties in this original rule,
1:43
but we're gonna select and cut out the
background-repeat, background-size and
1:48
padding-left declarations.
1:53
And we will scroll down and paste them in
our new contains selector rule.
1:55
All right, so let's take a look.
2:00
Once we save our stop sheet, and refresh
the page,
2:01
as we can see everything everything still
looks and works exactly the same.
2:04
But the difference is that the browser is
now matching the anchor elements that
2:09
contains downloads anywhere in the href
attribute.
2:13
So it's still matching the three download
links but
2:18
it's matching a different piece of the
href attribute's value.
2:20
Next, let's go over another useful example
of the contains selector.
2:24
So let's say that now we need to target
our thumbnail images and
2:29
apply a border and some margins.
2:33
Well, in our index.html file you'll notice
that the image elements
2:35
contained the word thumbnails in their
source attribute value.
2:40
So great.
2:45
We can actually use the word thumbnails
and
2:46
our selector as the piece of the source
value we'll want to target.
2:49
So let's create a selector for this.
2:53
So back in our .css file we'll create our
selector by
2:55
first targeting the image element,
followed by a set of square brackets.
2:58
Then we're going to define the source
attribute and
3:02
we'll again use the asterisk character.
3:05
To tell the browser that we're selecting
any image
3:09
whose source attribute contains the word,
thumbnails, anywhere in the value.
3:12
[BLANK_AUDIO]
3:17
In fact let's go ahead and use, thumb,
instead of, thumbnails.
3:21
Just so we can see how specific we can
actually get with the selector.
3:25
[SOUND] So now let's add a few CSS
properties inside our new rules.
3:28
So let's say margin four pixels let's add
a border property and
3:34
let's add the value to solid two pixels
and
3:40
we'll follow that with a width property.
3:44
Now let's set the width to 180 pixels and
set the height to 140 pixels.
3:49
All right, so let's go ahead and
3:56
save our style sheet and take a look at
our gallery.
3:57
Once we refresh the browser, we can see
how the browser targets and
4:00
styles all the thumbnails in our
galleries.
4:03
So, now, if all of our thumbnails need to
have these particular styles, it doesn't
4:06
matter how many we have on our page or in
our site, as long as the thumbnail source
4:12
points to the thumbnails directory, it
will still take on those styles.
4:18
And they'll all have that nice border and
the same width and height.
4:23
Similarly, if we need to target a
particular image without giving it
4:27
a class, we can still do that with the
contains attribute selector.
4:30
For example, to target the lake image
here, so
4:34
just the lake image we can tell the
browser.
4:39
To match the substring, lake, that's in
the source attribute.
4:42
So let's go ahead and do that.
4:46
Back in our style sheet, right beneath the
selector, we just start.
4:47
Let's once again target an image element.
4:51
And we're going to target the source
attribute, and we'll use the asterisk for
4:54
the contained selector.
4:59
And let's target the substring lake.
5:01
[BLANK_AUDIO]
5:04
And for this lake image we're gonna turn
the border color red.
5:07
All right.
5:11
So when we refresh the page.
5:15
Notice how the browser matches that lake image, because its
5:18
source value does in fact contain the word
lake somewhere in the value.
5:21
And it doesn't matter where in the value
as long as it's somewhere in the value.
5:25
In this case it's name of the image or if
we need to target say the bay image,
5:28
well we can change that and have the
browser.
5:34
Match the bay substring, and
5:38
as we can see when we refresh the page now
the bay image has that nice red border.
5:40
So, as we just learned these substring
matching attribute selectors can make our
5:46
CSS selectors more powerful because we're
able to target any part of
5:49
an attribute and we're not just limited to
the full value.
5:53
So let's go over when or
5:58
why we might wanna use some of the
structural pseudo classes or
5:59
substring matching attribute selectors in
place of regular ID's or class selectors.
6:03
As we learned, the special selectors can
come in handy when we don't have a lot of
6:08
control over the HTML.
6:12
For example we may be working with a
content management system or
6:14
framework that gives us little or no
access to
6:17
the html preventing us from being able to
add classes or IDs to certain elements.
6:20
They're also helpful when we have dynamic
content that's always changing, for
6:25
example a dynamic list or an image
gallery.
6:29
Having some of the structural pseudo
classes in place will prevent us from
6:33
constantly having to change the order of
classes in the HTML,
6:36
as we saw earlier in the first and last
child examples.
6:40
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