You’ve almost certainly encountered entities in HTML pages. They’re commonly used for international characters, mathematical operators, shapes, arrows and other symbols. For example:
These map directly to UTF-8 characters. The symbol for PI (π) can either be written as π or its UTF-8 number π. You can look-up popular symbols on the HTML Character Entity Reference to discover their HTML entity code and UTF-8 index number.
Entities in CSSAdding content via pseudo elements is increasingly common — especially if you’re using webfont icons. To add any UTF-8 character, you need to find its number and convert that to hexadecimal. For Pi, it’s 03C0. This can be added within a CSS file using a preceding backslash, e.g.
var pi = "u03C0";
That’s all there is to it. Simple solutions, but ones I always forget!
var copyright = "xA9";
How do I use character entities in HTML?
To use character entities in HTML, you need to start with an ampersand (&) followed by the entity name or number and then end with a semicolon (;). For example, to display a less than sign, you can use “<” or “<“. It’s important to note that HTML is case sensitive, so you must use the correct case when typing the entity name.
Can I use Unicode instead of character entities?
Yes, you can use Unicode instead of character entities. Unicode is a universal character encoding standard that includes almost every character from all writing systems. However, it’s important to note that not all browsers and systems support all Unicode characters, so it’s often safer to use character entities, especially for special characters.
How can I find the correct entity for a specific character?
There are many online resources where you can find a list of character entities. For example, the W3Schools website has a comprehensive HTML entity list. You can also use online tools like the HTML Entity Lookup to find the correct entity for a specific character.
Are there any limitations or issues with using character entities?
One of the main limitations of using character entities is that they can make your code harder to read, especially if you’re using a lot of them. Also, as mentioned earlier, not all browsers and systems support all character entities, so you may encounter compatibility issues.
Can I use character entities in attributes in HTML?
Yes, you can use character entities in attributes in HTML. However, it’s important to note that the quotation marks around the attribute value must not be escaped, as this would cause the HTML parser to interpret it incorrectly.
How do I use character entities in CSS?
In CSS, you can use character entities by starting with a backslash () followed by the hexadecimal value of the character. For example, to include a quotation mark, you can use “\0022”.
What is the difference between HTML entities and HTML character references?
HTML entities and HTML character references are essentially the same thing. The term “entity” is often used to refer to the named version (e.g., “&”), while “character reference” is often used to refer to the numeric version (e.g., “&”).
Can I create my own character entities?
No, you cannot create your own character entities. The set of character entities is defined by the HTML specification, and browsers only recognize these predefined entities. However, you can use Unicode to represent a wide range of characters.