<!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 Picture magnification technique ( A magnifying glass ) Implement code sharing - 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) {//Event normalization function
return W3CEvent || window.event;
}
function getPointerPosition(e) {//Browser-compatible mouse x,y get function
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) {//Compatible browsers set transparent values
if(elem.filters) {
elem.style.filter = 'alpha(opacity=' + level * 100 + ')';
} else {
elem.style.opacity = level;
}
}
function css(elem,prop) { //CSS Settings function, easy to set CSS values, and compatible with setting transparent values
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, //Load the div of the original image
img : null, //Enlarged image
mag : null, //Zoom box
scale : 15 //The scale, the bigger the scale, the bigger the scale, but the problem here is that if you don't divide, you're going to get some very small white edges, and I don't know how to solve that, right
}
css(m.img,{
'position' : 'absolute',
'width' : (m.cont.clientWidth * m.scale) + 'px', //The ratio of width * of the original image & PI;
'height' : (m.cont.clientHeight * m.scale) + 'px' //The high * scale value of the original image
})
css(m.mag,{
'display' : 'none',
'width' : m.cont.clientWidth + 'px', //M.ont is the original image, and the same width as the original image
'height' : m.cont.clientHeight + 'px',
'position' : 'absolute',
'left' : m.cont.offsetLeft + m.cont.offsetWidth + 10 + 'px',//The position of the zoom box is 10px to the far right of the original image
'top' : m.cont.offsetTop + 'px'
})
var borderWid = m.cont.getElementsByTagName('div')[0].offsetWidth - m.cont.getElementsByTagName('div')[0].clientWidth; //Gets the width of the border
css(m.cont.getElementsByTagName('div')[0],{ //M.c ont. GetElementsByTagName (' div ') [0] to browse box
'display' : 'none', //Set to invisible at first
'width' : m.cont.clientWidth / m.scale - borderWid + 'px', //The width/ratio value of the original image - the width of the border
'height' : m.cont.clientHeight / m.scale - borderWid + 'px',//The height/ratio value of the original image - the width of the border
'opacity' : 0.5//Set transparency
})
m.img.src = m.cont.getElementsByTagName('img')[0].src;//Allow the SRC value of the original image to be given to the enlarged image
m.cont.style.cursor = 'crosshair';
m.cont.onmouseover = magnifier.start;
},
start:function(e){
if(document.all){//Only under IE, mainly to avoid IE6 select can not be overridden
magnifier.createIframe(magnifier.m.img);
}
this.onmousemove = magnifier.move;//This points to m.c ont
this.onmouseout = magnifier.end;
},
move:function(e){
var pos = getPointerPosition(e); //Event normalization
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 = mouse x-this.offsetleft-browse box width /2, math.max and math.min so that the browse box does not exceed the image
})
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); //Destroy the 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="//www.jb51.net/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 test </option>
<option> Whether it can cover </option>
</select>
</body>
</html>