In CSS, elements can be positioned based on their attributes through attributes of the element. 1. The basic syntax is to wrap the attribute name in brackets. For example, input[type="text"] will select all input elements with type attribute "text". 2. The attribute selector supports multiple matching methods: exact match [attr=value], partial match [attr~=value], start with a specific value [attr|=value], contains substring [attr*=value], start with a certain string [attr^=value] and end [attr$=value]. 3. Actual applications include adding icons to different links, setting external link styles, setting download link styles according to file type, etc. 4. Pay attention to quotes, case sensitivity is usually insensitive, and multiple conditions can be combined, but avoid over-reliance on complex selectors to avoid affecting performance and maintenance.
In CSS, if you want to select an element based on its attributes, you can use the attribute selector . This selector is very useful, especially if you cannot locate elements by class name or ID.

1. Basic syntax: [屬性名]
The easiest attribute selector is to use brackets []
to wrap the attribute name directly. For example:
input[type="text"] { border: 1px solid #ccc; }
The above line of code will select all <input>
elements with type
attribute "text"
and add border styles to them.

2. Exact match and fuzzy match
The attribute selector not only supports precise matching, but also partial matching to meet different selection needs:
Exact match :
[attr=value]
For example,[lang="en"]
will select the element oflang="en"
but will not matchlang="en-US"
.A value is included in a space-separated list :
[attr~=value]
For example,[class~="highlight"]
will match elements likeclass="highlight important"
.Start with a specific value (separated with a hyphen) :
[attr|=value]
Suitable for scenarios such as language coding, such as[lang|="en"]
that can matchlang="en"
orlang="en-US"
.The attribute value contains a substring :
[attr*=value]
For example,[src*="logo"]
can matchsrc="images/logo.png"
.The attribute value begins with a string :
[attr^=value]
For example,[href^="https"]
can select all HTTPS links.The attribute value ends with a string :
[attr$=value]
For example,[src$=".jpg"]
can be used to filter JPG images.
3. Examples of practical application scenarios
Property selectors are widely used in actual development, and the following are some common examples:
Add different icons to different types of links:
a[href^="mailto:"]::before { content: "??"; }
Special style processing for external links:
a[href^="http"] { color: purple; rel: noopener; }
Set the download link style according to the file type:
a[href$=".pdf"]::after { content: " (PDF)"; font-size: 0.8em; color: gray; }
4. Precautions and tips
- If the attribute value is a string, remember to add quotation marks, either or even.
- Whether the property selector is case sensitive depends on the HTML document type. It is usually case-insensitive in HTML.
- Multiple attribute conditions can be used in combination, for example:
input[type="text"][disabled] { background: #eee; }
- Do not over-rely rely on complex selectors, otherwise it will affect maintainability and performance.
Basically that's it. Although the attribute selector is simple, it is very useful in actual layout and style control, especially when there is no class name or ID, it can help you accurately locate the target elements.
The above is the detailed content of How to select an element by its attribute in CSS?. For more information, please follow other related articles on the PHP Chinese website!

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