电子商务网站经常用到简单模仿一下,用得着的点击"html"选项卡可以复制源码
当鼠标移动到缩略小图上时，在它上面显示半透明的放大蒙板并计算其位置，移开时隐藏半透明的放大蒙板
鼠标指针移动到放大蒙板的中心才会开始移动蒙板，半透明蒙版位置计算：鼠标指针当前位置 - 图片的位置 - 蒙版的宽度/2。
根据比例计算出大图的偏移
代码
View Code
<!DOCTYPE html>
<html>
<head>
<meta charset="gb2312" />
<title>放大镜</title>
<style>
img{ vertical-align:bottom;}
.mod_zoom{ overflow:hidden; zoom:1;}
.mod_zoom .p1 { float:left; position:relative; height:350px; width:350px; margin-right:5px; cursor:crosshair; }
.mod_zoom .p1 .mask{ position:absolute; left:0; top:0; width:175px; height:175px; background-color:#fede4f; opacity:0.3; filter: alpha(opacity=30); display:none;}
.mod_zoom .p2{ position:relative; width:400px; height:400px; overflow:hidden; display:none;}
.mod_zoom .p2 .img{ position:absolute; left:0; top:0;}
</style>
</head>
<body>
<div>
<div class="mod_zoom">
<div class="p1" id="p1">
<img src="http://img14.360buyimg.com/n1/4071/b350e77e-fc74-4173-81b5-dfe54f425ef6.jpg" id="z1" />
<span class="mask" id="m"></span>
</div>
<div class="p2" id="p2">
<img src="http://img14.360buyimg.com/n0/4071/b350e77e-fc74-4173-81b5-dfe54f425ef6.jpg" class="img" id="z2" />
</div>
</div>
</div>
<script>
function PhotoZoomer(elements){
this.mask = elements.mask; //蒙版
this.container = elements.container //原图容器
this.originimg = elements.originimg; //原图
this.bigContainer = elements.bigContainer; //大图容器
this.bigimg = elements.bigimg; //大图
this.visible = false;
this._bind();
}
PhotoZoomer.prototype = {
display: function(style){
var self = this;
self.mask.style.display = style;
self.bigContainer.style.display = style;
},
//计算放大蒙版位置
zoom: function(clientX, clientY){
var self = this,
//位置比例
rate = {},
//放大蒙版最大活动范围
maxrange = {
offsetLeft: self.container.offsetWidth - self.mask.offsetWidth,
offsetTop: self.container.offsetHeight - self.mask.offsetHeight
},
//mask left
left = clientX - self.container.offsetLeft - self.mask.offsetWidth/2,
//mask top
top = clientY - self.container.offsetTop - self.mask.offsetHeight/2;
if(left < 0) {
left = 0;
}else if(left> maxrange.offsetLeft) {
left = maxrange.offsetLeft;
}
if(top < 0) {
top = 0;
}else if(top > maxrange.offsetTop){
top = maxrange.offsetTop;
}
//alert(maxrange.offsetTop);
rate.left = left / maxrange.offsetLeft;
rate.top = top / maxrange.offsetTop;
self.mask.style.left = left + 'px';
self.mask.style.top = top + 'px';
self.bigimg.style.left = -rate.left * (self.bigimg.offsetWidth - self.bigContainer.offsetWidth) + "px";
self.bigimg.style.top = -rate.top * (self.bigimg.offsetHeight - self.bigContainer.offsetHeight) + "px";
},
_bind: function(){
var self = this;
self.container.onmouseover = function(e){
e = e || window.event;
var target = e.targe || e.srcElement;
self.display("block");
this.visible = true;
};
self.container.onmouseout = function(e){
e = e || window.event;
var target = e.targe || e.srcElement;
self.display("none");
this.visible = false;
};
self.container.onmousemove = function(e){
e = e || window.event;
if(!this.visible )return;//防止元素大小计算错误
self.zoom(e.clientX, e.clientY);
};
}
};
function get(id){
return document.getElementById(id)
}
var elements = {
mask: get("m"),
container: get("p1"),
originimg: get("z1"),
bigContainer: get("p2"),
bigimg: get("z2")
};
var zoomer = new PhotoZoomer(elements);
// alert(elements.container.offsetParent.tagName)
</script>
</body>
</html>