The slideshow effect is a way to combine multiple pictures The effect of switching pictures in a certain order. When implementing slide effects, JavaScript event listening and CSS style control are required. <\/p>

(1) Preparation<\/p>

Similarly, in the HTML file, a div container needs to be defined to display the slide. We can define multiple img elements, each img element contains a picture. <\/p>

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In the CSS file, we need to style these elements. For example, set the width and height of the div container to the actual size of the image, and set the overflow attribute to hidden; set the position of all img elements to absolute so that they can overlap; and set all but the first image The image's transparency is set to 0. <\/p>
#slideshow {\n  width: 600px;\n  height: 400px;\n  overflow: hidden;\n  position: relative;\n}\n\n#slideshow img {\n  position: absolute;\n  top: 0;\n  left: 0;\n  opacity: 0;\n}\n\n#slideshow img:first-child {\n  opacity: 1;\n}<\/pre>
In the above code, we use the :first-child pseudo-class to set the transparency of the first image to 1. <\/p>
(2) Slideshow implementation<\/p>
Next, we need to use JavaScript functions to achieve the slideshow effect. The specific process is as follows: <\/p>
① Define a variable index to record the serial number of the currently displayed picture. <\/p>
var index = 1;<\/pre>
② Write a function to switch pictures and update the value of the index variable. In this function, we first set the transparency of the currently displayed image to 0, then add 1 to the value of the index variable, and determine whether the total number of images is exceeded. If exceeded, reset it to 1. Then set the transparency of the next image to 1 and animate it. <\/p>
function show() {\n  $(\"#slideshow img:nth-child(\" + index + \")\").stop().animate({opacity: 0}, 1000); \/\/ 當(dāng)前圖片透明度減少\n  index++;\n  if (index > 4) {\n    index = 1;\n  }\n  $(\"#slideshow img:nth-child(\" + index + \")\").stop().animate({opacity: 1}, 1000); \/\/ 下一張圖片透明度增加\n}<\/pre>
In the above code, we use the :nth-child selector, which can select a child element under the specified parent element. In this example, we use this selector to select the index image. <\/p>
③ Use the setInterval() method to execute the show function regularly. <\/p>
$(function () {\n  setInterval(show, 3000);\n})<\/pre>
In the above code, we use the $() method and setInterval() method of the jQuery library to implement scheduled calls. The $() method is used to obtain the specified element, and the setInterval() method can call the specified function periodically. <\/p>
Finally, the implementation code of the entire slide effect is as follows: <\/p>
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