I saw a feature on some web pages with many pictures. When the scroll bar on the right side of the web page is pulled down, the pictures below are slowly displayed, and some have a gradual display effect. I found that this effect is good and can improve the opening speed of web pages. I searched online for a long time before I found out that this is called the "image asynchronous loading" function. I searched online and found the complete code. I posted it here for everyone to learn from.
