What are the characteristics of fixed positioning?

The characteristics of fixed positioning include positioning relative to the browser window, out of the normal document flow, unavailable keyboard focus, not supporting relative positioning and absolute positioning, only available in non-static contexts, used to create tool tips and Modal box, used with top, right, bottom and left attributes, does not support animation effects, used with z-index attribute, print layout will not be affected, etc. Fixed positioning is a convenient and useful CSS layout technique for creating always-visible tooltips, modals, and other elements that need to be fixed to the screen.

The operating system for this tutorial: Windows 10 system, DELL G3 computer.

Fixed Positioning (Fixed Positioning) is a CSS positioning strategy that gives an element a fixed position relative to the browser window. Even if the page is scrolled, it will always remain in the same position. The following are some characteristics of fixed positioning:

1. Positioning relative to the browser window: Fixed positioning positions the element relative to the browser window, rather than relative to the rest of the document. This means that when the page scrolls, fixedly positioned elements will remain in the same position and will not move with the rest of the document content.

2. Breaking away from the normal document flow: Fixed-positioned elements are "fixed" from the normal document flow and will not be affected by other elements. This means that it does not affect the layout of other elements, nor is it affected by the layout of other elements.

3. Unavailable keyboard focus: Since fixedly positioned elements do not move as the page scrolls, they are unavailable for keyboard focus. This means that users using keyboard navigation do not have direct access to these elements.

4. Relative positioning and absolute positioning are not supported: In fixed positioning, the position of an element is relative to the browser window, not to its containing block or other elements. Therefore, fixed positioning does not support the concepts of relative and absolute positioning.

5. Only available in non-static context: Fixed positioning is only available when the context of the element is not static (that is, position: static is not specified). In a static context, elements are positioned by default, which is based on document flow.

6. Can be used to create tool tips and modal boxes: Fixed positioning is often used to create effects such as tool tips (Tooltips) and modal windows (Modal Windows). By anchoring an element to a certain location on the screen, you can create a tooltip or modal that is always visible, regardless of page scrolling.

7. Can be used with the top, right, bottom and left attributes: Fixed positioning can achieve the precise position of the element by setting the top, right, bottom and left attributes of the element. These properties specify the distance of the element from the border of the browser window, thereby achieving a fixed positioning effect.

8. Animation effects are not supported: Fixed positioning does not support animation effects. Once an element is fixed, its position cannot be changed via CSS animations.

9. Can be used with the z-index attribute: Although fixedly positioned elements will not be obscured by other elements, they can be located above or below other elements, depending on their z-index value. By setting the z-index attribute, you can control the stacking order of fixed elements.

10. Not affected in print layout: Fixed positioning is not affected in print layout. This means that when the document is printed, fixedly positioned elements will print according to their position in the browser window.

In short, fixed positioning is a convenient and practical CSS layout technique suitable for creating always-visible tooltips, modal boxes, and other elements that need to be fixed on the screen. However, it is important to note that when using fixed positioning, ensure that it does not negatively impact the user experience, especially in terms of accessibility.

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