div rotation in jquery-Front-end Q&A-php.cn

div rotation in jquery

王林

Release： 2023-05-08 15:29:10

Original

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jQuery is one of the most popular JavaScript libraries currently, and it provides developers with many tools to simplify code and simplify the development process. It supports various animation effects, making web pages more dynamic. Among them, div rotation is a common animation effect. The following will introduce how to use jQuery to achieve div rotation.

1. Understand the basic concepts

Before we start using jQuery to implement div rotation, we need to understand some basic concepts.

CSS3 rotation attribute

CSS3 rotation attribute transform is the key to achieving div rotation. Its syntax format is as follows:

transform: rotate(angle);

Among them, the angle can be a positive number or a negative number, indicating the angle of rotation.

jQuery’s animate() method

jQuery’s animate() method is used to achieve animation effects. Its syntax format is as follows:

$(selector).animate({params},speed,callback);

Parameter description:

selector: jQuery selection Container, representing the element that needs animation.
params: animation effect parameters, which can be key-value pairs of CSS properties. For example, {width: ‘500px’, height: ‘500px’}.
speed: animation duration, expressed in milliseconds, such as 1000ms.
callback: callback function after the animation is completed.

By calling the animate() method, we can make the div element rotate during the animation process, thereby achieving the effect of div rotation.

2. Implementation code

Below, we will introduce in detail how to use jQuery to achieve the animation effect of div rotation.

Step 1: Create HTML and CSS files

First, we need to create an HTML file and a CSS style file.

HTML file content is as follows:

<!DOCTYPE html>
<html>
<head>
  <title>jQuery旋转div示例</title>
  <meta charset="utf-8">
  <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
  <link rel="stylesheet" type="text/css" href="style.css">
</head>
<body>
  <div id="box"></div>
  <button id="rotateBtn">旋转</button>
</body>
<script src="script.js"></script>
</html>

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CSS file content is as follows:

#box{
  width: 100px;
  height: 100px;
  background-color: #00FF7F;
  margin: 100px auto;
  transition: all 1s;
}

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This code creates a div with a background color of #00FF7F and a width and height of 100px , displayed in the center. Among them, the transition attribute defines the time required for the div to go from one state to another, in seconds.

We also added a button to trigger the div rotation animation effect.

Step 2: Write JavaScript code

In the HTML file, we introduced a JavaScript file named "script.js". In this file, we will use jQuery to animate the div rotation.

The code is as follows:

$(function(){
  $("#rotateBtn").click(function(){
    $("#box").animate({deg: '+=90'}, {
      duration: "slow",
      step: function(now){
        $(this).css({
          transform: 'rotate(' + now + 'deg)'
        });
      }
    });
  });
});

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This code is divided into two parts:

(1) After clicking the button, call the animate() method to trigger the animation effect of div rotation.

$("#box").animate({deg: '+=90'}, {
  duration: "slow",
  step: function(now){
    $(this).css({
      transform: 'rotate(' + now + 'deg)'
    });
  }
});

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Among them, the first parameter is the animation effect parameter, and deg is a custom attribute we have used to record the angle of rotation. When the button is clicked, adding 90 degrees to the deg attribute of the div element can achieve the effect of rotating 90 degrees.

The second parameter is an object used to set the duration of the animation and the callback function for each step of the animation. Note that here we use the step callback function to control the rotation angle of each step to achieve the effect of div rotation.

(2) Write a callback function

step: function(now){
  $(this).css({
    transform: 'rotate(' + now + 'deg)'
  });
}

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In the callback function, we update the rotation angle of the div and dynamically control the rotation angle by passing the now value to the transform attribute.

3. Running Example

Now, we have completed the code for div rotation and can run it through the browser to view the effect. During the running process, we can click the "Rotate" button to achieve the rotation effect of the div element.

In addition, we can also achieve richer animation effects by modifying the relevant properties of the CSS style file. For example, different animation effects can be achieved by modifying parameters such as the length of the transition time and the speed of rotation.

In short, it is very simple to use jQuery to achieve div rotation animation effects. You only need to understand the usage rules of CSS3 rotation properties and jQuery's animate() method, and you can easily achieve various desired rotation effects.

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