css3，背景中间透明：
background-image: linear-gradient(red, red 25%, transparent 25%, transparent 75%, red 75%, red 100%), linear-gradient(to right, red, red 25%, transparent 25%, transparent 75%, red 75%, red 100%)
//淡入效果(含淡入到指定透明度)function fadeIn(elem, speed, opacity){
/*
* 参数说明
* elem==>需要淡入的元素
* speed==>淡入速度,正整数(可选)
* opacity==>淡入到指定的透明度,0~100(可选)
*/
speed = speed || 20
opacity = opacity || 100
//显示元素,并将元素值为0透明度(不可见)
elem.style.display = 'block'
iBase.SetOpacity(elem, 0)
//初始化透明度变化值为0
var val = 0
//循环将透明值以5递增,即淡入效果
(function(){
iBase.SetOpacity(elem, val)
val += 5
if (val <= opacity) {
setTimeout(arguments.callee, speed)
}
})()
}
//淡出效果(含淡出到指定透明度)
function fadeOut(elem, speed, opacity){
/*
* 参数说明
* elem==>需要淡入的元素
* speed==>淡入速度,正整数(可选)
* opacity==>淡入到指定的透明度,0~100(可选)
*/
speed = speed || 20
opacity = opacity || 0
//初始化透明度变化值为0
var val = 100
//循环将透明值以5递减,即淡出效果
(function(){
iBase.SetOpacity(elem, val)
val -= 5
if (val >= opacity) {
setTimeout(arguments.callee, speed)
}else if (val < 0) {
//元素透明度为0后隐藏元素
elem.style.display = 'none'
}
})()
}
var btns = document.getElementById('demo')
btns.onclick = function(){
fadeIn(btns)
}
btns.onclick = function(){
fadeOut(btns,40)
}
<p id="demo" style="width:300pxheight:300pxbackground:#f00">淡入淡出</p>
试试吧
