How to use CSS Positions layout to achieve waterfall flow effect on web pages

How to use CSS Positions layout to achieve the waterfall flow effect of web pages

Waterfall flow layout is a common web page layout method. It is characterized by elements arranged in an irregular manner. Arranged on the page, they flow from top to bottom like a waterfall. Waterfall flow layout is widely used in picture display, product display and other scenarios in web design. It can make good use of page space and display more content. In this article, we will introduce how to achieve the waterfall effect of web pages by using CSS Positions layout.

First, create a container containing multiple sub-elements in HTML to display the content of the waterfall flow layout. Each child element represents a single item or picture that will be displayed.

<div class="waterfall-container">
  <div class="item">Item 1</div>
  <div class="item">Item 2</div>
  <div class="item">Item 3</div>
  ...
</div>

Next, you need to define CSS styles to implement waterfall layout. First, set the width and minimum height of the container, and use position: relative to position the child elements relative to the container.

.waterfall-container {
  width: 100%;
  min-height: 400px;
  position: relative;
}

Then, use position: absolute to position the child elements. We will use JavaScript to generate random heights for child elements so that we can achieve the waterfall effect. Here, we assume that there is already a JavaScript function named randomHeight() that can return a random number.

.item {
  width: 200px;
  position: absolute;
  padding: 10px;
  /* 元素水平间距和垂直间距 */
  margin: 10px;
  /* 定位子元素的初始位置 */
  top: 0;
  left: 0;
}

Next, we need to use JavaScript to calculate and apply the position of each child element. We will use two arrays columnHeights and columnIndexes to hold the height and index of each column.

var columnHeights = [0, 0, 0]; // 初始每列高度为0
var columnIndexes = [0, 1, 2]; // 初始每列索引为0, 1, 2
var columnCount = 3; // 列数
var itemWidth = 200; // 子元素宽度
var horizontalMargin = 20; // 水平间距
var verticalMargin = 20; // 垂直间距

var items = document.getElementsByClassName("item");
for (var i = 0; i < items.length; i++) {
  var shortestColumnHeight = Math.min.apply(null, columnHeights);
  var shortestColumnIndex = columnHeights.indexOf(shortestColumnHeight);

  items[i].style.top = columnHeights[shortestColumnIndex] + "px";
  items[i].style.left = shortestColumnIndex * (itemWidth + horizontalMargin) + "px";

  columnHeights[shortestColumnIndex] += items[i].offsetHeight + verticalMargin;
}

Through the above code, we can calculate and apply the position of sub-elements based on the height and index of each column, thereby achieving the effect of waterfall flow layout on the web page.

Finally, through the combination of CSS styles and JavaScript code, we can achieve the effect of waterfall flow layout on the web page. Of course, you can adjust the style and code according to actual needs to make it more consistent with your design requirements.

To summarize, the key to using CSS Positions layout to achieve the waterfall flow effect of web pages is to use position: absolute to position sub-elements, and use JavaScript to calculate and apply the position of each sub-element. With reasonable style settings and code calculations, we can easily implement a beautiful waterfall flow layout.

Reference:

• W3Schools - CSS Positions: [https://www.w3schools.com/csS/css_positioning.asp](https://www.w3schools.com /csS/css_positioning.asp)
• MDN Web Docs - position: [https://developer.mozilla.org/en-US/docs/Web/CSS/position](https://developer.mozilla .org/en-US/docs/Web/CSS/position)

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