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The principle and usage of HTML fixed positioning
1. The principle of fixed positioning
In HTML, fixed positioning is a kind of relative positioning relative to browsing How to position the browser window. When an element is set to fixed positioning, it is positioned relative to the visible area of the browser window and does not move as the scroll bar scrolls.
The key to achieving fixed positioning is to use the position attribute and top, bottom, left, and right attributes in CSS. The position attribute can take two values, namely relative and fixed. When set to fixed, the element will be set to fixed positioning.
2. How to use fixed positioning
Below we will introduce the use of fixed positioning in detail and provide specific code examples.
First, we need to create an element in the HTML document and set its style to fixed-positioning. You can use the div tag to create a container and set a unique ID as an identifier. The sample code is as follows:
<div id="fixed-element"> <!-- 这里是元素的内容 --> </div>
Next, we need to use CSS to style the elements, including positioning and other style attributes. First, we need to set the element to fixed positioning using the position attribute. In this example, we set the element to a fixed positioning of the upper left corner, that is, the distance from the left and top is 0. The sample code is as follows:
#fixed-element { position: fixed; top: 0; left: 0; }
In addition to positioning attributes, you can also set other styles as needed, such as background color, size, border, etc.
Finally, we need to apply the above styles to elements in the page. This can be achieved by adding a style tag within the head tag of the HTML document. The sample code is as follows:
<!DOCTYPE html> <html> <head> <style> #fixed-element { position: fixed; top: 0; left: 0; } </style> </head> <body> <div id="fixed-element"> <!-- 这里是元素的内容 --> </div> </body> </html>
In addition to basic fixed positioning, you can also go further by setting the values of the top, bottom, left, and right attributes. Adjust the position of the element. For example, you can set the element to a fixed positioning of the lower right corner, that is, the distance from the right and bottom is 0. The sample code is as follows:
#fixed-element { position: fixed; bottom: 0; right: 0; }
In addition, you can also use fixed positioning in combination with other positioning methods, such as absolute positioning, to achieve more complex layout effects.
Summary:
By using fixed positioning, we can create elements that appear at a fixed position within the browser window. By setting the position attribute to fixed and adjusting the values of the top, bottom, left, and right attributes, you can flexibly control the position of the element. In actual applications, the style can be further adjusted as needed and combined with other CSS properties to achieve richer layout effects.
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