<!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圖片放大技術(放大鏡)實現代碼分享 - www.companysz.com</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) {//事件標準化函數
return W3CEvent || window.event;
}
function getPointerPosition(e) {//兼容瀏覽器的鼠標x,y獲得函數
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) {//兼容瀏覽器設置透明值
if(elem.filters) {
elem.style.filter = 'alpha(opacity=' + level * 100 + ')';
} else {
elem.style.opacity = level;
}
}
function css(elem,prop) { //css設置函數,可以方便設置css值,并且兼容設置透明值
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, //裝載原始圖像的div
img : null, //放大的圖像
mag : null, //放大框
scale : 15 //比例值,設置的值越大放大越大,但是這里有個問題就是如果不可以整除時,會產生些很小的白邊,目前不知道如何解決
}
css(m.img,{
'position' : 'absolute',
'width' : (m.cont.clientWidth * m.scale) + 'px', //原始圖像的寬*比例值
'height' : (m.cont.clientHeight * m.scale) + 'px' //原始圖像的高*比例值
})
css(m.mag,{
'display' : 'none',
'width' : m.cont.clientWidth + 'px', //m.cont為原始圖像,與原始圖像等寬
'height' : m.cont.clientHeight + 'px',
'position' : 'absolute',
'left' : m.cont.offsetLeft + m.cont.offsetWidth + 10 + 'px',//放大框的位置為原始圖像的右方遠10px
'top' : m.cont.offsetTop + 'px'
})
var borderWid = m.cont.getElementsByTagName('div')[0].offsetWidth - m.cont.getElementsByTagName('div')[0].clientWidth; //獲取border的寬
css(m.cont.getElementsByTagName('div')[0],{ //m.cont.getElementsByTagName('div')[0]為瀏覽框
'display' : 'none', //開始設置為不可見
'width' : m.cont.clientWidth / m.scale - borderWid + 'px', //原始圖片的寬/比例值 - border的寬度
'height' : m.cont.clientHeight / m.scale - borderWid + 'px',//原始圖片的高/比例值 - border的寬度
'opacity' : 0.5//設置透明度
})
m.img.src = m.cont.getElementsByTagName('img')[0].src;//讓原始圖像的src值給予放大圖像
m.cont.style.cursor = 'crosshair';
m.cont.onmouseover = magnifier.start;
},
start:function(e){
if(document.all){//只在IE下執行,主要避免IE6的select無法覆蓋
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); //事件標準化
this.getElementsByTagName('div')[0].style.display = '';
css(this.getElementsByTagName('div')[0],{
'top' : Math.min(Math.max(pos.y - this.offsetTop - parseInt(this.getElementsByTagName('div')[0].style.height) / 2,0),this.clientHeight - this.getElementsByTagName('div')[0].offsetHeight) + 'px',
'left' : Math.min(Math.max(pos.x - this.offsetLeft - parseInt(this.getElementsByTagName('div')[0].style.width) / 2,0),this.clientWidth - this.getElementsByTagName('div')[0].offsetWidth) + 'px' //left=鼠標x - this.offsetLeft - 瀏覽框寬/2,Math.max和Math.min讓瀏覽框不會超出圖像
})
magnifier.m.mag.style.display = '';
css(magnifier.m.img,{
'top' : - (parseInt(this.getElementsByTagName('div')[0].style.top) * magnifier.m.scale) + 'px',
'left' : - (parseInt(this.getElementsByTagName('div')[0].style.left) * magnifier.m.scale) + 'px'
})
},
end:function(e){
this.getElementsByTagName('div')[0].style.display = 'none';
magnifier.removeIframe(magnifier.m.img); //銷毀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>
<div id="magnifier">
<img src="http://www.companysz.com/images/20091107/fangda.jpg" id="img" />
<div id="Browser"></div>
</div>
<div id="mag"><img id="magnifierImg" /></div>
<select style="position:absolute;top:200px;left:650px;width:100px;">
<option>select測試</option>
<option>是否能覆蓋</option>
</select>
</body>
</html>
