Detailed explanation of CSS serial number properties: counter and list-style-type

Detailed explanation of CSS serial number attributes: counter and list-style-type

Introduction:
In web design, we often encounter the need to create lists or titles, etc. element number. In order to meet different design needs, CSS provides two important attributes: counter and list-style-type. This article will detail the usage of these two properties and provide some specific code examples.

1. Counter attribute:
The counter attribute allows developers to create custom counters for numbering or marking elements. It contains two important attributes: counter-increment and counter-reset.

1. counter-increment: The
   counter-increment attribute defines the rules for incrementing the counter. It accepts the names of one or more counters and specifies their incrementing rules. Commonly used values ​​include integers (1, -1), percentages, numbers, and none. Here is an example:

body {
  counter-reset: chapter;
}

h1::before {
  counter-increment: chapter;
  content: "Chapter " counter(chapter) ": ";
}

In this example, first use counter-reset to reset the counter named chapter to 0. Then, insert the counter value in front of the h1 element through the counter-increment attribute and add "Chapter " and ": " to the content.

2. counter-reset: The
   counter-reset attribute is used to define the initial value of the counter. It accepts the names of one or more counters and specifies their initial values. Commonly used values ​​include integers, percentages, and none. Here is an example:

ol {
  counter-reset: my-counter;
  list-style-type: none;
}

li::before {
  counter-increment: my-counter;
  content: counter(my-counter) ". ";
}

In this example, first use counter-reset to reset the counter named my-counter to 0. Then, insert the counter value in front of the li element via the counter-increment attribute and add "." to the content.

2. list-style-type attribute:
list-style-type attribute is used to set the tag type of list items. It accepts some predefined values ​​such as decimal, lower-alpha, upper-roman, etc. Here are some commonly used values ​​and corresponding examples:

1. disc:
   Mark list items as solid dots.

ul {
  list-style-type: disc;
}

2. decimal:
   Mark list items as numbers (1, 2, 3).

ol {
  list-style-type: decimal;
}

3. lower-alpha:
   Mark list items as lowercase letters (a, b, c).

ol {
  list-style-type: lower-alpha;
}

4. upper-roman:
   Mark list items with uppercase Roman numerals (I, II, III).

ol {
  list-style-type: upper-roman;
}

Conclusion:
By using the counter and list-style-type attributes, developers can easily customize the numbering and tag types of elements. This article introduces the basic usage of counter and list-style-type attributes and provides some specific code examples for readers' reference. I hope readers can use these two attributes flexibly to achieve various web design effects based on these examples.

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