Does sticky positioning break away from the document flow?

Is sticky positioning separated from the document flow? Specific code examples are needed

In web development, layout is a very important topic. Among them, positioning is one of the commonly used layout techniques. In CSS, there are three common positioning methods: static positioning, relative positioning and absolute positioning. In addition to these three positioning methods, there is also a more special positioning method, namely sticky positioning. So, does sticky positioning break away from the document flow? Let’s discuss it in detail below and provide some code examples to help understand.

First of all, we need to understand what document flow is. In an HTML document, elements are arranged in the order they appear in the document. This is the document flow. In other words, the position of an element in the document is determined by its previous elements. If an element breaks away from the document flow, it will no longer be affected by the previous elements, that is, it will no longer be arranged in the normal document flow order.

Next, let’s take a look at sticky positioning. Sticky positioning is a new positioning method introduced in CSS3, which allows elements to be fixed on the screen when scrolled to a specific position. Sticky positioning can be achieved by setting position: sticky;. The specific code is as follows:

.sticky-element {
  position: sticky;
  top: 0;
}

In this example, we set the position of an element to sticky positioning and fix it at the top of the screen. As the page scrolls, the element stays at the top of the screen until it scrolls to another specific location.

So, does sticky positioning break away from the document flow? The answer is not complete disengagement. Although sticky positioning allows an element to stay on the screen when scrolled to a specific position, it will still occupy its original position. That is, other elements before and after an element's sticky positioning will still be affected by it and will be arranged according to their position in the document flow. Only when an element scrolls completely off the screen does it completely break out of the document flow.

Here we can use a specific example to illustrate. Suppose there is a navigation bar fixed to the top of the screen, with a piece of text below it. We want the text to not be obscured when the navigation bar is fixed to the top of the screen, i.e. the text appears below the navigation bar. The code is as follows:

<div class="sticky-element"></div>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nunc malesuada convallis ornare. In pretium purus at sapien maximus feugiat. Fusce egestas dignissim tortor, at bibendum erat viverra vitae. Aliquam erat volutpat. Aenean vitae metus a est pellentesque sodales. Sed eleifend metus id dui tincidunt, eget auctor ligula tempor. Proin posuere libero vitae pharetra tempus.</p>

.sticky-element {
  position: sticky;
  top: 0;
  background-color: #f8f8f8;
  padding: 10px;
}

In this example, the height of the navigation bar is 40px, so we add a margin- for the

tag The value of top is 40px so that the text will not be obscured by the navigation bar.

To sum up, although sticky positioning will be fixed on the screen when scrolling to a specific position, it does not completely break away from the document flow and will still occupy the original position. Through specific code examples, we can better understand the characteristics and usage of sticky positioning. Hope this article can be helpful to you!

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