How to realize percentage display in javascript step bar

When developing a web page or application, the step bar is a very important element. It can help users clearly understand the current progress and how much work remains to be completed. Typically, a step bar should show the number of steps the user has completed and the number of steps yet to be completed, and it needs to accurately display the current progress percentage. In this article, we'll show you how to display a step bar with a percentage using JavaScript.

Step 1: HTML structure

First, we need to create the skeleton of a step bar in HTML. We can use a simple unordered list (ul) and some numbered list items (li), as shown below:

  
•     1     步骤一   
  
•     2     步骤二   
  
•     3     步骤三   
  
•     4     步骤四   

We can see that each list item contains a step number ( Represented by the <span class="step"></span> element) and a title (represented by the <span class="title"></span> element). In the first list item, we also use the active class to represent the current step.

Step 2: CSS Style

Next, we need to define the style for the step bar in CSS. We will use flexbox to align and layout the list items as follows:

.progress {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  list-style: none;
}

.progress li {
  flex: 1;
  text-align: center;
  position: relative;
  z-index: 1;
}

.progress li.active::before {
  content: '';
  position: absolute;
  top: 50%;
  left: -50%;
  width: 200%;
  height: 4px;
  background-color: #4caf50;
  transform: translateY(-50%);
  z-index: -1;
}

.progress .step {
  display: block;
  width: 30px;
  height: 30px;
  line-height: 30px;
  border-radius: 50%;
  background-color: #f2f2f2;
  color: #999;
  margin-bottom: 10px;
}

.progress li.active .step {
  background-color: #4caf50;
  color: #fff;
}

.progress .title {
  display: block;
  font-size: 12px;
  color: #777;
  text-transform: uppercase;
  margin-bottom: 5px;
}

.progress li:first-child .title {
  text-align: left;
}

.progress li:last-child .title {
  text-align: right;
}

In this CSS style, we have used flexbox to vertically align each list item and justify-content: space-between Leave some space between each list item. We also use pseudo-elements ::before and position: absolute to present the current step background color and percentage progress bar. Notice that we also added corresponding styles for the step number and title in each list item.

Step Three: JavaScript Code

Finally, we need to write some JavaScript code to calculate the progress percentage and display it in the step bar. For each list item, we count the number of steps completed and the total number of steps individually, and then display the percentage of progress in the element next to the step number. We can use the following code to achieve this:

// 获取步骤条的UL元素
const progress = document.querySelector('.progress');

// 获取步骤条中的所有列表项
const steps = progress.querySelectorAll('li');

// 遍历每个列表项
steps.forEach((step, index) => {
  // 获取当前列表项的步骤号
  const stepNumber = step.querySelector('.step');

  // 计算已完成的步骤数和总步骤数
  const completed = index;
  const total = steps.length - 1;

  // 计算进度的百分比
  const percent = Math.round((completed / total) * 100);

  // 在步骤号旁边的元素中显示百分比
  stepNumber.innerHTML = `${percent}%`;
});

Note that we used the Math.round() function in this code to round the calculated progress percentage to an integer, This avoids display problems caused by decimal place errors.

Finally, we can save the above code to our HTML file and open the file to see the effect of the step bar and its percentage progress. Is not it simple? With the above steps, we can easily create a step bar with percentage progress and give users a clear understanding of their current progress.

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