Home >Web Front-end >JS Tutorial >Try to make a javascript magnifying glass effect_javascript skills

Try to make a javascript magnifying glass effect_javascript skills

WBOYOriginal: 2016-05-16 15:23:311315browse

The example in this article introduces the principle and code of implementing the magnifying glass effect based on JavaScript, and shares it with you for your reference. The specific content is as follows:

Principle:

A: Magnifying glass B: Small picture

C: Large picture visible area

D: Big picture

The mouse position should be in the center of the magnifying glass, so the mouse position is:

clientX=A.offsetLeft()+B.offsetLeft+1/2*A.offsetWidth;

clientY=A.offsetTop()+B.offsetTop+1/2*A.offsetHeight;

During the mouse movement: Magnifying glass A and large picture D move together in proportion to the mouse, because when the right border of magnifying glass A moves to coincide with the right border of small picture B, large picture D should also move to the right The border overlaps the right border of C, so their movement ratio is : (D.offsetWidth-C.offsetWidth)/(B.offsetWidth-A.offsetWidth)=b/a

HTML part:

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>放大镜效果</title>

<style>

*{
margin:0;
padding:0; 
}

#demo{
position: relative;
margin:30px 50px;
width: 1000px;
height: 600px;
border: 1px solid #000;
}

#zhezhao{
position: absolute;
z-index:2;
background:red;
width:402px;
height:402px;
left: 20px;
top:20px;
opacity: 0;
}

#small{
position: absolute;
width:402px;
height:402px;
left: 20px;
top:20px;
border: 1px solid #000;
z-index: 1;
}


#small img{
position: absolute;

}


#big{
position: relative;
top: 20px;
left: 460px;
width:500px;
height:500px;
border: 1px solid #000;
overflow: hidden;
display: none;
z-index: 1;
}


#big img{
position: absolute;

}


#glass{
position: absolute;
width:100px;
height: 100px;
opacity: 0.3;
background:orange;
display: none;
}

</style>


</head>


<body>
<div id='demo'>
<div id='zhezhao'> </div> 
<!-- 在ie浏览器中，当鼠标在放大镜上是，浏览器并不认为鼠标同样在小图的div上，所以加个遮罩层 兼容ie-->


<div id='small'> 
<img src='images/small.png' alt=''>
<div id='glass'></div>
</div>
<div id='big'>
<img src='images/big.jpg' alt='' >

</div>

</div>



</body>

</html>

js part:

<script>

window.onload=function(){
var demo =document.getElementById('demo');
var small =document.getElementById('small');
var big =document.getElementById('big');
var glass =document.getElementById('glass')
var image =document.getElementById('big').getElementsByTagName('img')[0];
var zhezhao=document.getElementById('zhezhao');

zhezhao.onmouseover=function(){
glass.style.display='block'
big.style.display='block'
}
zhezhao.onmouseout=function(){
glass.style.display='none'
big.style.display='none'
}

//弄清楚clientX，offsetLeft，left的关系，注意区分
zhezhao.onmousemove=function(ev){
var event=ev
var left=event.clientX-demo.offsetLeft-small.offsetLeft-glass.offsetWidth/2;
var top =event.clientY-demo.offsetTop -small.offsetTop -glass.offsetHeight/2;
if(left<0){
left=0;
}else if(left>(small.offsetWidth-glass.offsetWidth)){
left=small.offsetWidth-glass.offsetWidth
}

if(top<0){
top=0;
}else if(top>(small.offsetHeight- glass.offsetHeight)){
top=small.offsetHeight- glass.offsetHeight
}
glass.style.left =left+'px';
glass.style.top =top+'px';

 

var percent=(image.offsetWidth-big.offsetWidth)/(small.offsetWidth-glass.offsetWidth)

image.style.left=-percent*left+'px'
image.style.top =-percent*top+'px'



}
}

</script>

The above is the entire content of this article. I hope it will be helpful to everyone in realizing the javascript magnifying glass effect.

Statement：

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Previous article：Sharing useful information: Let you learn javascript closures in minutes_javascript skillsNext article：Sharing useful information: Let you learn javascript closures in minutes_javascript skills

See more

Try to make a javascript magnifying glass effect_javascript skills

Related articles