How to implement mouse-over magnification effect on images with JavaScript?-JS Tutorial-php.cn

How to implement mouse-over magnification effect on images with JavaScript?

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Release： 2023-10-20 09:16:45

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JavaScript 如何实现图片鼠标悬停放大效果？

JavaScript How to achieve the mouse-over magnification effect of an image?

Nowadays, web design pays more and more attention to user experience, and many web pages will add some special effects to pictures. Among them, the picture mouse-over magnification effect is a common special effect, which can automatically enlarge the picture when the user hovers the mouse, increasing the interaction between the user and the picture. This article will introduce how to use JavaScript to achieve this effect and give specific code examples.

Idea analysis:
To achieve the mouse-over magnification effect of the picture, we can use JavaScript to listen to the mouse movement event and add some dynamic styles to the picture to achieve the magnification effect. The specific implementation steps are as follows:

Get the picture element: Use the JavaScript selector to get the picture element that needs to be enlarged.
Add mouse movement event listener: Use JavaScript event listener to listen for mouse movement events on the picture. When the mouse moves over the picture, the corresponding processing function is triggered.
Modify the style of the picture: In the processing function, you can achieve the enlargement effect by modifying the related style of the picture. You can use the transform property of CSS to scale the size of the image, or you can do it by modifying the width and height properties of the image.

The specific code implementation is as follows:

<!DOCTYPE html>
<html>
<head>
<style>
    .zoom-img {
        transition: transform 0.2s;
    }
</style>
</head>
<body>
    <img src="image.jpg" class="zoom-img" id="zoomImg" alt="放大图片">
    
    <script>
        var img = document.getElementById("zoomImg");
        img.addEventListener("mousemove", handleMouseMove);
        
        function handleMouseMove(event) {
            var x = event.clientX;
            var y = event.clientY;
            
            var width = img.offsetWidth;
            var height = img.offsetHeight;
            
            var dx = x - (width / 2 + img.offsetLeft);
            var dy = y - (height / 2 + img.offsetTop);
            
            var scaleX = 1.1;
            var scaleY = 1.1;
            
            img.style.transform = "scale(" + scaleX + ", " + scaleY + ")";
            img.style.transformOrigin = (dx / width) * 100 + "% " + (dy / height) * 100 + "%";
        }
        
        img.addEventListener("mouseout", handleMouseOut);
        
        function handleMouseOut(event) {
            img.style.transform = "";
            img.style.transformOrigin = "";
        }
    </script>
</body>
</html>

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In the above code, we added a zoom-img class to the image element and added it in the JavaScript code The element is obtained through the getElementById method. Then we use the addEventListener method to add two event listeners, one is the mousemove event to handle the movement of the mouse on the picture, and the other is the mouseout The event is used to handle the effect restoration when the mouse leaves the picture.

In the handleMouseMove function, we obtain the coordinates of the mouse in the window and calculate the coordinates relative to the center point of the picture. Then the magnification ratio and the zoom center point are calculated based on this coordinate value. When modifying the style, the transform attribute is used to achieve the zoom effect of the image.

In the handleMouseOut function, we reset the transform and transformOrigin properties of the image to empty strings to restore the image to its original state .

In this way, when the mouse moves over the picture, the picture will be enlarged according to the position of the mouse, increasing the interaction between the user and the picture.

Summary:
Using JavaScript to implement the mouse-over magnification effect of images can add some dynamic special effects to the web page and improve the user experience. During the implementation process, we need to listen to the mouse movement event and modify the image style to achieve the magnification effect. Specific code implementation can be adjusted and expanded according to actual needs. I hope this article can help you understand how to achieve the mouse-over magnification effect of images.

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