This article introduces the JavaScript image magnification technology (magnifying glass) implementation code. Friends in need can refer to it
The specific code is as follows:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>JavaScript图片放大技术(放大镜)实现代码分享 - www.jb51.net</title>
<style type="text/css">
#magnifier{
width:342px;
height:420px;
position:absolute;
top:100px;
left:250px;
font-size:0;
border:1px solid #000;
}
#img{
width:342px;
height:420px;
}
#Browser{
border:1px solid #000;
z-index:100;
position:absolute;
background:#555;
}
#mag{
border:1px solid #000;
overflow:hidden;
z-index:100;
}
</style>
<script type="text/javascript">
function getEventObject(W3CEvent) {//事件标准化函数
return W3CEvent || window.event;
}
function getPointerPosition(e) {//兼容浏览器的鼠标x,y获得函数
e = e || getEventObject(e);
var x = e.pageX || (e.clientX + (document.documentElement.scrollLeft || document.body.scrollLeft));
var y = e.pageY || (e.clientY + (document.documentElement.scrollTop || document.body.scrollTop));
return { 'x':x,'y':y };
}
function setOpacity(elem,level) {//兼容浏览器设置透明值
if(elem.filters) {
elem.style.filter = 'alpha(opacity=' + level * 100 + ')';
} else {
elem.style.opacity = level;
}
}
function css(elem,prop) { //css设置函数,可以方便设置css值,并且兼容设置透明值
for(var i in prop) {
if(i == 'opacity') {
setOpacity(elem,prop[i]);
} else {
elem.style[i] = prop[i];
}
}
return elem;
}
var magnifier = {
m : null,
init:function(magni){
var m = this.m = magni || {
cont : null, //装载原始图像的p
img : null, //放大的图像
mag : null, //放大框
scale : 15 //比例值,设置的值越大放大越大,但是这里有个问题就是如果不可以整除时,会产生些很小的白边,目前不知道如何解决
}
css(m.img,{
'position' : 'absolute',
'width' : (m.cont.clientWidth * m.scale) + 'px', //原始图像的宽*比例值
'height' : (m.cont.clientHeight * m.scale) + 'px' //原始图像的高*比例值
})
css(m.mag,{
'display' : 'none',
'width' : m.cont.clientWidth + 'px', //m.cont为原始图像,与原始图像等宽
'height' : m.cont.clientHeight + 'px',
'position' : 'absolute',
'left' : m.cont.offsetLeft + m.cont.offsetWidth + 10 + 'px',//放大框的位置为原始图像的右方远10px
'top' : m.cont.offsetTop + 'px'
})
var borderWid = m.cont.getElementsByTagName('p')[0].offsetWidth - m.cont.getElementsByTagName('p')[0].clientWidth; //获取border的宽
css(m.cont.getElementsByTagName('p')[0],{ //m.cont.getElementsByTagName('p')[0]为浏览框
'display' : 'none', //开始设置为不可见
'width' : m.cont.clientWidth / m.scale - borderWid + 'px', //原始图片的宽/比例值 - border的宽度
'height' : m.cont.clientHeight / m.scale - borderWid + 'px',//原始图片的高/比例值 - border的宽度
'opacity' : 0.5//设置透明度
})
m.img.src = m.cont.getElementsByTagName('img')[0].src;//让原始图像的src值给予放大图像
m.cont.style.cursor = 'crosshair';
m.cont.onmouseover = magnifier.start;
},
start:function(e){
if(document.all){//只在IE下执行,主要避免IE6的select无法覆盖
magnifier.createIframe(magnifier.m.img);
}
this.onmousemove = magnifier.move;//this指向m.cont
this.onmouseout = magnifier.end;
},
move:function(e){
var pos = getPointerPosition(e); //事件标准化
this.getElementsByTagName('p')[0].style.display = '';
css(this.getElementsByTagName('p')[0],{
'top' : Math.min(Math.max(pos.y - this.offsetTop - parseInt(this.getElementsByTagName('p')[0].style.height) / 2,0),this.clientHeight - this.getElementsByTagName('p')[0].offsetHeight) + 'px',
'left' : Math.min(Math.max(pos.x - this.offsetLeft - parseInt(this.getElementsByTagName('p')[0].style.width) / 2,0),this.clientWidth - this.getElementsByTagName('p')[0].offsetWidth) + 'px' //left=鼠标x - this.offsetLeft - 浏览框宽/2,Math.max和Math.min让浏览框不会超出图像
})
magnifier.m.mag.style.display = '';
css(magnifier.m.img,{
'top' : - (parseInt(this.getElementsByTagName('p')[0].style.top) * magnifier.m.scale) + 'px',
'left' : - (parseInt(this.getElementsByTagName('p')[0].style.left) * magnifier.m.scale) + 'px'
})
},
end:function(e){
this.getElementsByTagName('p')[0].style.display = 'none';
magnifier.removeIframe(magnifier.m.img); //销毁iframe
magnifier.m.mag.style.display = 'none';
},
createIframe:function(elem){
var layer = document.createElement('iframe');
layer.tabIndex = '-1';
layer.src = 'javascript:false;';
elem.parentNode.appendChild(layer);
layer.style.width = elem.offsetWidth + 'px';
layer.style.height = elem.offsetHeight + 'px';
},
removeIframe:function(elem){
var layers = elem.parentNode.getElementsByTagName('iframe');
while(layers.length >0){
layers[0].parentNode.removeChild(layers[0]);
}
}
}
window.onload = function(){
magnifier.init({
cont : document.getElementById('magnifier'),
img : document.getElementById('magnifierImg'),
mag : document.getElementById('mag'),
scale : 3
});
}
</script>
</head>
<body>
<p id="magnifier">
<img src="//www.jb51.net/images/20091107/fangda.jpg" id="img" />
<p id="Browser"></p>
</p>
<p id="mag"><img id="magnifierImg" /></p>
<select style="position:absolute;top:200px;left:650px;width:100px;">
<option>select测试</option>
<option>是否能覆盖</option>
</select>
</body>
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