javascript automatically disappears prompt

When developing web applications, it is often necessary to provide some prompt information to users. These prompt messages can be used to guide the user to the next step, or to warn the user that certain operations may lead to irreversible consequences. Generally speaking, these prompts need to be closed manually by the user, but in some cases, we hope that the prompts will disappear automatically within a certain period of time. This article will introduce how to use javascript to automatically disappear prompt information.

1. Preparation

In order to realize the automatic disappearing prompt information, we need to use the following technology:

• HTML/CSS: used to create The appearance and layout of the prompt information.
• JavaScript: used to control the performance and behavior of prompt information.

First, create a container in HTML to hold the prompt information. You can use a fixed div element, as shown below:

<div id="alert-container"></div>

Secondly, use CSS styles to control the appearance and layout of this container. To keep the container always at the top of the page, use the position:fixed attribute. In order to make the container fill the entire window, you can set the top, left, right, and bottom properties to 0. In addition, in order to make the container look more beautiful, you can set some styles for the container, such as background color, border, etc.

#alert-container {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: #fff;
  border: 1px solid #ccc;
  box-shadow: 0px 0px 10px #ccc;
  padding: 20px;
  font-size: 16px;
  color: #000;
  text-align: center;
}

Now, we are ready to display the container with prompt information.

2. Display prompt information

Next, we need to write code to display prompt information. In JavaScript, you can use the DOM API to create and modify HTML elements. In order to make the prompt information disappear automatically, we can first use the setTimeout function to control the time when the prompt information is displayed, and then use the DOM API to dynamically add the prompt information to the container, and add an event listener to the prompt information so that when the user clicks The prompt message is automatically deleted when the button is closed.

The following is a sample code that creates an alert function that will display prompt information in the container and automatically delete it after a certain period of time.

function alert(msg, duration) {
  var container = document.getElementById('alert-container');
  var alert = document.createElement('div');
  alert.innerHTML = msg;
  alert.setAttribute('class', 'alert');
  container.appendChild(alert);
  setTimeout(function() {
    alert.parentNode.removeChild(alert);
  }, duration);
}

In this function, we first obtain the container element, and then create a new div element, which contains the prompt information. We also set a class attribute to set specific styles for the tooltip in the CSS stylesheet.

Next, we add the newly created div element to the container.

Finally, we use the setTimeout function to set a timer to delete the prompt information after a certain period of time. We used the parentNode and removeChild functions to remove the prompt information. In this way, when the user clicks the close button, the automatic removal process is actually called, because the event handler of the close button removes the element with the prompt information from the DOM.

3. Using the prompt message

Now, we have prepared the JavaScript code for displaying the automatic disappearing prompt message. To use this feature in your application, just call the alert function and pass it a message and a duration.

For example:

alert('操作成功！', 3000); // 在3秒后自动消失

This will display a prompt message in the container to prompt the user that the operation is successful, and it will automatically disappear after 3 seconds.

4. Summary

When developing web applications, prompt information is a very common requirement. Using JavaScript, you can easily realize automatic disappearing prompt information, which can improve the user experience and reduce the user's operational burden. If you want to learn more JavaScript skills, you can check out more JavaScript tutorials.

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