<!DOCTYPE html> <html> <head> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <style> * {box-sizing: border-box;} .img-magnifier-container { position:relative; } .img-magnifier-glass { position: absolute; border: 3px solid #000; border-radius: 50%; cursor: none; /*设置放大镜的大小：*/ width: 100px; height: 100px; } </style> <script> function magnify(imgID, zoom) { var img, glass, w, h, bw; img = document.getElementById(imgID); /* 创建放大镜：*/ glass = document.createElement("DIV"); glass.setAttribute("class", "img-magnifier-glass"); /*插入放大镜:*/ img.parentElement.insertBefore(glass, img); /* 设置放大镜的背景属性：*/ glass.style.backgroundImage = "url('" + img.src + "')"; glass.style.backgroundRepeat = "no-repeat"; glass.style.backgroundSize = (img.width * zoom) + "px " + (img.height * zoom) + "px"; bw = 3; w = glass.offsetWidth / 2; h = glass.offsetHeight / 2; /*当有人在图像上移动放大镜时执行一个函数：*/ glass.addEventListener("mousemove", moveMagnifier); img.addEventListener("mousemove", moveMagnifier); /* 也适用于触摸屏：*/ glass.addEventListener("touchmove", moveMagnifier); img.addEventListener("touchmove", moveMagnifier); function moveMagnifier(e) { var pos, x, y; /*防止在图像上移动时可能发生的任何其他操作*/ e.preventDefault(); /*获取光标的x和y位置：*/ pos = getCursorPos(e); x = pos.x; y = pos.y; /* 防止放大镜位于图像之外：*/ if (x > img.width - (w / zoom)) {x = img.width - (w / zoom);} if (x < w / zoom) {x = w / zoom;} if (y > img.height - (h / zoom)) {y = img.height - (h / zoom);} if (y < h / zoom) {y = h / zoom;} /*设置放大镜的位置：*/ glass.style.left = (x - w) + "px"; glass.style.top = (y - h) + "px"; /*显示放大镜“看到”的内容：*/ glass.style.backgroundPosition = "-" + ((x * zoom) - w + bw) + "px -" + ((y * zoom) - h + bw) + "px"; } function getCursorPos(e) { var a, x = 0, y = 0; e = e || window.event; /*获取图像的x和y位置：*/ a = img.getBoundingClientRect(); /*计算光标相对于图像的 x 和 y 坐标：*/ x = e.pageX - a.left; y = e.pageY - a.top; /*考虑任何页面滚动：*/ x = x - window.pageXOffset; y = y - window.pageYOffset; return {x : x, y : y}; } } </script> </head> <body> <h1>图像放大镜</h1> <p>鼠标悬停在图片上：</p> <div class="img-magnifier-container"> <img id="myimage" src="..." alt="图片" width="600" height="400"> </div> <p>可以随意更改放大镜的强度</p> <script> /* 启动放大功能 带有图像的 ID 和放大镜的强度：*/ magnify("myimage", 7); </script> </body> </html>