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How to operate JS to implement transparency gradient animation
- php中世界最好的语言Original
- 2018-06-01 14:40:491607browse
This time I will show you how to operate JS to achieve transparency gradient animation. What are the precautions for operating JS to achieve transparency gradient animation? The following is a practical case, let’s take a look.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>JS透明度变化效果</title>
<style>
body{
margin: 0px;
padding: 0px;
}
.redb{
width:200px;
height: 200px;
background: red;
filter:alpha(opacity=30);
opacity: 0.3;
}
</style>
</head>
<body>
<p class="redb" id="opbtn"></p>
<script>
window.onload = function(){
var opp = document.getElementById("opbtn");
opp.onmouseover = function(){
startMove(100);
}
opp.onmouseout = function(){
startMove(30);
}
}
var timer = null;
var alpha = 30;
var speed = 0;
function startMove(opTarget){
clearInterval(timer);
var opp = document.getElementById("opbtn");
timer = setInterval(function(){
if(alpha<opTarget){
speed = 10;
}
else if(alpha>opTarget){
speed = -10;
}
if(alpha==opTarget){
clearInterval(timer);
}
else{
alpha += speed;
opp.style.opacity = alpha/100;
opp.style.filter = 'alpha(opacity='+alpha+')';
}
},100);
}
</script>
</body>
</html>
Summary:
1. The difference between filter and opacity: w3c standard transparency is opacity, filter can only be used by IE, other browsers support opacity2 . When changing the transparency, the transparency value cannot be obtained through a method similar to offsetLeft, so you need to create a separate variable
3. Don’t forget to assign the
timer to timer
Using the cache call chain to implement JS method overloading steps Detailed explanation
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