道理
- 在做div或许图片淡入淡出的时刻,我们重要用到了透明度款式filter: alpha(opacity:30)兼容ie,opacity:0.3兼容火狐chrome。
- 活动淡入淡出时用到了定时器setInterval;clearInterval;
- js操纵淡入淡出时用下面情势修正透明度oDiv.style.filter=”alpha(opacity:”+alpha+”)”;oDiv.style.opacity=alpha/100;
注重:透明度没法直接在js中做推断,我们采纳alpha参数做比较,末了应用到对象上。
完成div淡入淡出
<!DOCTYPE html>
<html>
<head>
<title>div淡入淡出</title>
<style>
#div1{
width: 200px;
height: 200px;
background: red;
/* ie */
filter: alpha(opacity:30);
/* chrome firefox */
opacity:0.3;
}
</style>
<script>
window.onload=function(){
var oDiv=document.getElementById("div1");
oDiv.onmouseover=function(){
startMove(100);
}
oDiv.onmouseout=function(){
startMove(30);
}
}
var timer=null;
var alpha=30;//透明度默许30
function startMove(iTarget){
var oDiv=document.getElementById("div1");
clearInterval(timer);
timer=setInterval(function(){
var speed=0;
if(alpha<iTarget){
speed=5;
}else{
speed=-5;
}
if(alpha===iTarget){
clearInterval(timer);
}else{
alpha+=speed;
oDiv.style.filter="alpha(opacity:"+alpha+")";
oDiv.style.opacity=alpha/100;
}
},30);
}
</script>
</head>
<body>
<div id="div1"></div>
</body>
</html>
完成图片淡入淡出
<!DOCTYPE html>
<html>
<head>
<title>图片淡入淡出</title>
<style>
#img1{
/* ie */
filter: alpha(opacity:30);
/* chrome firefox */
opacity: 0.3;
border: 1px solid #000;
}
</style>
<script>
window.onload=function(){
var oImg=document.getElementById("img1");
oImg.onmouseover=function(){
startMove(100);
}
oImg.onmouseout=function(){
startMove(30);
}
}
var timer=null;
var alpha=30;//透明度默许30
function startMove(iTarget){
var oImg=document.getElementById("img1");
clearInterval(timer);
timer=setInterval(function(){
var speed=0;
if(alpha<iTarget){
speed=5;
}else{
speed=-5;
}
if(alpha===iTarget){
clearInterval(timer);
}else{
alpha+=speed;
oImg.style.filter="alpha(opacity:"+alpha+")";
oImg.style.opacity=alpha/100;
}
},30);
}
</script>
</head>
<body>
<img id="img1" src="img1.jpg" alt="">
</body>
</html>