Home Web Front-end JS Tutorial JS motion effects

JS motion effects

Jun 09, 2018 pm 04:12 PM
js

This article mainly introduces the perfect motion framework of JS motion special effects, and analyzes the relevant operating techniques of JavaScript for element attribute detection and judgment in motion in the form of examples. Friends in need can refer to the examples of this article

Describes the motion framework of JS motion special effects. Share it with everyone for your reference, the details are as follows:

As mentioned in the previous article "JS Motion Special Effects Simultaneous Movement", there is still a problem in our motion framework. So what is the problem? Adjust the program in the previous article

op.onmouseover = function () {
   //startMove(op,{width:300,height:300,opacity:30});
   startMove(op,{width:204,height:300,opacity:30});
}
Copy after login

When the mouse moves in, let's change the width not to 300, but to 204, and see what changes there will be? ?

As can be seen from the picture, when the mouse moves in, Only the width reaches the expected value of 204, while the height Neither the target value nor the opacity have reached the target value (the target value is 300 and 0.3), why is that? ? It is caused by the following problem

if(objAttr == json[attr]){
    clearInterval(obj.timer);
    if(fn){
      fn();
    }
}
Copy after login

The if statement only determines when objAttr is equal to the target value and clears the timer (that is to sayAs long as an attribute reaches the target value, it enters if, clear the timer), it is not judged that "all movements" have reached the target value; the width quickly reaches the target value from 200 to 204, while the height and opacity are still halfway there; However, since the width has reached the target value, the if statement is entered to clear the timer. Width, height, and opacity use a timer, so at this time, the height and opacity are frozen halfway and can never reach the target value.

How to solve that? ? ?

1. When enters the timer, set a flag var flag and use it to detect whether all movements have reached the target value

function startMove(obj,json,fn) {
      clearInterval(obj.timer);
      obj.timer = setInterval(function () {
       var flag = true;// 一进入定时器设置标志位
      },30);
}
var flag = true;// 表示所有的运动都到达目标值
var flag = false;// 表示有的运动没有到达目标值
Copy after login

2. Then make a judgment in the statement to detect whether the motion has stopped##

if(objAttr != json[attr]){// 判断是否所有的运动都达到目标值
     // 进入if语句,说明至少有一个 运动未到达目标值
     flag = false;
}
Copy after login
for...in. Change each attribute in the loop (widht , height, opacity...), as long as one attribute change does not reach the target value, the value of the flag flag is false; then

#throughout the entire for...in..loop Externally judge the value of the flag. If it is still true, it means that "all movements" have reached the target value. At this time, the timer can be cleared.

for(attr in json){
}
if(flag){// 再次判断flag的值
  clearInterval(obj.timer);
  if(fn){
    fn();
  }
}
Copy after login

The timer is executed every 30 milliseconds, each time it is entered First set

var flag =true, and then execute downwards. Each time, you must judge

if(objAttr != json[attr]){ ... }As long as there is a movement that does not reach the target value, it will enter the execution of the if statement and set the flag to false. When the timer is executed for the last time, it is found that all attributes have reached the target value. At this time, the if statement is no longer true. There is no chance to set the flag to false, so the last time the timer flag is entered is always true; then the conditions of if(flag){ ... } are met, and then if( flag){ ... }Execute.

It’s perfect here, take a look at the effect

##Complete test code:Hhtm part and css part are exactly the same as the previous article. The js code is as follows

<script>
    window.onload = function(){
      var op = document.getElementById(&#39;p1&#39;);
      op.onmouseover = function () {
        //startMove(op,{width:300,height:300,opacity:30});
        startMove(op,{width:204,height:300,opacity:30});
      }
      op.onmouseout = function () {
        startMove(op,{width:200,height:200,opacity:100});
      }
    }
    function getStyle(obj,attr){
      return getComputedStyle ? getComputedStyle(obj,false)[attr] : obj.currentStyle[attr];
    }
    function startMove(obj,json,fn) {
      clearInterval(obj.timer);
      obj.timer = setInterval(function () {
        var bStop = true;
        for(attr in json){
          // 1. 取得当前的值(可以是widht,height,opacity等的值)
          var objAttr = 0;
          if(attr == "opacity"){
            objAttr = Math.round(parseFloat(getStyle(obj,attr))*100);
          }else{
            objAttr = parseInt(getStyle(obj,attr));
          }
          // 2.计算运动速度
          var iSpeed = (json[attr] -objAttr)/10;
            iSpeed = iSpeed>0 ?Math.ceil(iSpeed):Math.floor(iSpeed);
          // 3. 检测所有运动是否到达目标
          if(objAttr != json[attr]){
            bStop = false;
          }
          if(attr == "opacity"){
            obj.style.filter = &#39;alpha(opacity:&#39;+(objAttr+iSpeed)+&#39;)&#39;;
            obj.style.opacity = (objAttr+iSpeed)/100;
          }else{
            obj.style[attr] = objAttr+iSpeed+&#39;px&#39;;// 需要又.属性名的形式改成[]
          }
        }
        if(bStop){ // 表示所有运动都到达目标值
          clearInterval(obj.timer);
          if(fn){
            fn();
          }
        }
      },30);
    }
</script>
Copy after login

The above is what I compiled for everyone. I hope it will be helpful to everyone in the future.

Related articles:

Using vue to implement secondary route setting method

react project development

Achieve multiple routing implementations in Vue-Router2.X

Detailed interpretation of react controlled components and uncontrolled components

The above is the detailed content of JS motion effects. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Recommended: Excellent JS open source face detection and recognition project Recommended: Excellent JS open source face detection and recognition project Apr 03, 2024 am 11:55 AM

Face detection and recognition technology is already a relatively mature and widely used technology. Currently, the most widely used Internet application language is JS. Implementing face detection and recognition on the Web front-end has advantages and disadvantages compared to back-end face recognition. Advantages include reducing network interaction and real-time recognition, which greatly shortens user waiting time and improves user experience; disadvantages include: being limited by model size, the accuracy is also limited. How to use js to implement face detection on the web? In order to implement face recognition on the Web, you need to be familiar with related programming languages ​​and technologies, such as JavaScript, HTML, CSS, WebRTC, etc. At the same time, you also need to master relevant computer vision and artificial intelligence technologies. It is worth noting that due to the design of the Web side

How to use JS and Baidu Maps to implement map pan function How to use JS and Baidu Maps to implement map pan function Nov 21, 2023 am 10:00 AM

How to use JS and Baidu Map to implement map pan function Baidu Map is a widely used map service platform, which is often used in web development to display geographical information, positioning and other functions. This article will introduce how to use JS and Baidu Map API to implement the map pan function, and provide specific code examples. 1. Preparation Before using Baidu Map API, you first need to apply for a developer account on Baidu Map Open Platform (http://lbsyun.baidu.com/) and create an application. Creation completed

Essential tools for stock analysis: Learn the steps to draw candle charts with PHP and JS Essential tools for stock analysis: Learn the steps to draw candle charts with PHP and JS Dec 17, 2023 pm 06:55 PM

Essential tools for stock analysis: Learn the steps to draw candle charts in PHP and JS. Specific code examples are required. With the rapid development of the Internet and technology, stock trading has become one of the important ways for many investors. Stock analysis is an important part of investor decision-making, and candle charts are widely used in technical analysis. Learning how to draw candle charts using PHP and JS will provide investors with more intuitive information to help them make better decisions. A candlestick chart is a technical chart that displays stock prices in the form of candlesticks. It shows the stock price

How to create a stock candlestick chart using PHP and JS How to create a stock candlestick chart using PHP and JS Dec 17, 2023 am 08:08 AM

How to use PHP and JS to create a stock candle chart. A stock candle chart is a common technical analysis graphic in the stock market. It helps investors understand stocks more intuitively by drawing data such as the opening price, closing price, highest price and lowest price of the stock. price fluctuations. This article will teach you how to create stock candle charts using PHP and JS, with specific code examples. 1. Preparation Before starting, we need to prepare the following environment: 1. A server running PHP 2. A browser that supports HTML5 and Canvas 3

How to use JS and Baidu Map to implement map click event processing function How to use JS and Baidu Map to implement map click event processing function Nov 21, 2023 am 11:11 AM

Overview of how to use JS and Baidu Maps to implement map click event processing: In web development, it is often necessary to use map functions to display geographical location and geographical information. Click event processing on the map is a commonly used and important part of the map function. This article will introduce how to use JS and Baidu Map API to implement the click event processing function of the map, and give specific code examples. Steps: Import the API file of Baidu Map. First, import the file of Baidu Map API in the HTML file. This can be achieved through the following code:

How to use JS and Baidu Maps to implement map heat map function How to use JS and Baidu Maps to implement map heat map function Nov 21, 2023 am 09:33 AM

How to use JS and Baidu Maps to implement the map heat map function Introduction: With the rapid development of the Internet and mobile devices, maps have become a common application scenario. As a visual display method, heat maps can help us understand the distribution of data more intuitively. This article will introduce how to use JS and Baidu Map API to implement the map heat map function, and provide specific code examples. Preparation work: Before starting, you need to prepare the following items: a Baidu developer account, create an application, and obtain the corresponding AP

PHP and JS Development Tips: Master the Method of Drawing Stock Candle Charts PHP and JS Development Tips: Master the Method of Drawing Stock Candle Charts Dec 18, 2023 pm 03:39 PM

With the rapid development of Internet finance, stock investment has become the choice of more and more people. In stock trading, candle charts are a commonly used technical analysis method. It can show the changing trend of stock prices and help investors make more accurate decisions. This article will introduce the development skills of PHP and JS, lead readers to understand how to draw stock candle charts, and provide specific code examples. 1. Understanding Stock Candle Charts Before introducing how to draw stock candle charts, we first need to understand what a candle chart is. Candlestick charts were developed by the Japanese

The relationship between js and vue The relationship between js and vue Mar 11, 2024 pm 05:21 PM

The relationship between js and vue: 1. JS as the cornerstone of Web development; 2. The rise of Vue.js as a front-end framework; 3. The complementary relationship between JS and Vue; 4. The practical application of JS and Vue.

See all articles