What are the grammatical structures of the id selector?

The id selector is a selector in CSS used to select HTML elements with specified IDs. The syntax structure is "#id{/* CSS style rules */ }", where the # symbol indicates that this is an id selector, followed by the ID name of the element to be selected, such as "#header".

This Tutorial operating system: Windows 10 system, Dell G3 computer.

The id selector is a selector in CSS used to select HTML elements with specified IDs. Its syntax structure is as follows:

#id {
  /* CSS 样式规则 */
}

where , the # symbol indicates that this is an id selector, followed by the ID name of the element to be selected, such as #header.

It should be noted that the ID name in the id selector must be unique and cannot be repeated Use. If there are multiple elements with the same ID name, only the first matching element will be selected.

In addition, the ID name can contain letters, numbers, hyphens, and underscores, but cannot start with a number. For example, #my-id and #nav-bar are legal ID names, but #1st-element is not a legal ID name.

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