html5 拖动效果在手机上实现方法是调用drag和drop一系列函数实现的。
注意：拖拽源在拖拽操作结束将得到dragend事件对象，不管操作成功与否。
举例：
定义可拖放内容
<div id="columns">
<div class="column" draggable="true"><header>A</header></div>
<div class="column" draggable="true"><header>B</header></div>
<div class="column" draggable="true"><header>C</header></div>
</div>
2、监听拖动事件
可附加大量不同事件以监听整个拖放过程：
dragstart
drag
dragenter
dragleave
dragover
drop
dragend
a.这里是开始拖拽
function handleDragStart(e) {
this.style.opacity = '0.4' // this / e.target is the source node.
}
var cols = document.querySelectorAll('#columns .column')
[].forEach.call(cols, function(col) {
col.addEventListener('dragstart', handleDragStart, false)
})
b.dragenter、dragover 和 dragleave 事件处理程序可用于在拖动过程中提供额外的可视化提示。例如，在拖动期间将鼠标悬停在某一列上方时，其边框可能会变成虚线。这样，用户就能知道这些列也是放置的目标区域。
使用浏览器可以进行手机效果测试：
现在各大浏览器都有这种功能了， 谷歌、QQ、360搜狐等；
首先打开网页，点击右键列表里会有“审查元素”，再点击手机那个按钮，就可以调整屏幕宽度查看手机效果。
<!DOCTYPE html><html>
<head>
<meta charset="utf-8">
<title>粒子漩涡特效</title>
<style>
html,body{
margin:0px
width:100%
height:100%
overflow:hidden
background:#000
}
#canvas{
position:absolute
width:100%
height:100%
}
</style>
</head>
<body>
<canvas id="canvas"></canvas>
<script>
function project3D(x,y,z,vars){
var p,d
x-=vars.camX
y-=vars.camY-8
z-=vars.camZ
p=Math.atan2(x,z)
d=Math.sqrt(x*x+z*z)
x=Math.sin(p-vars.yaw)*d
z=Math.cos(p-vars.yaw)*d
p=Math.atan2(y,z)
d=Math.sqrt(y*y+z*z)
y=Math.sin(p-vars.pitch)*d
z=Math.cos(p-vars.pitch)*d
var rx1=-1000
var ry1=1
var rx2=1000
var ry2=1
var rx3=0
var ry3=0
var rx4=x
var ry4=z
var uc=(ry4-ry3)*(rx2-rx1)-(rx4-rx3)*(ry2-ry1)
var ua=((rx4-rx3)*(ry1-ry3)-(ry4-ry3)*(rx1-rx3))/uc
var ub=((rx2-rx1)*(ry1-ry3)-(ry2-ry1)*(rx1-rx3))/uc
if(!z)z=0.000000001
if(ua>0&&ua<1&&ub>0&&ub<1){
return {
x:vars.cx+(rx1+ua*(rx2-rx1))*vars.scale,
y:vars.cy+y/z*vars.scale,
d:(x*x+y*y+z*z)
}
}else{
return { d:-1 }
}
}
function elevation(x,y,z){
var dist = Math.sqrt(x*x+y*y+z*z)
if(dist &&z/dist>=-1 &&z/dist <=1) return Math.acos(z / dist)
return 0.00000001
}
function rgb(col){
col += 0.000001
var r = parseInt((0.5+Math.sin(col)*0.5)*16)
var g = parseInt((0.5+Math.cos(col)*0.5)*16)
var b = parseInt((0.5-Math.sin(col)*0.5)*16)
return "#"+r.toString(16)+g.toString(16)+b.toString(16)
}
function interpolateColors(RGB1,RGB2,degree){
var w2=degree
var w1=1-w2
return [w1*RGB1[0]+w2*RGB2[0],w1*RGB1[1]+w2*RGB2[1],w1*RGB1[2]+w2*RGB2[2]]
}
function rgbArray(col){
col += 0.000001
var r = parseInt((0.5+Math.sin(col)*0.5)*256)
var g = parseInt((0.5+Math.cos(col)*0.5)*256)
var b = parseInt((0.5-Math.sin(col)*0.5)*256)
return [r, g, b]
}
function colorString(arr){
var r = parseInt(arr[0])
var g = parseInt(arr[1])
var b = parseInt(arr[2])
return "#"+("0" + r.toString(16) ).slice (-2)+("0" + g.toString(16) ).slice (-2)+("0" + b.toString(16) ).slice (-2)
}
function process(vars){
if(vars.points.length<vars.initParticles) for(var i=0i<5++i) spawnParticle(vars)
var p,d,t
p = Math.atan2(vars.camX, vars.camZ)
d = Math.sqrt(vars.camX * vars.camX + vars.camZ * vars.camZ)
d -= Math.sin(vars.frameNo / 80) / 25
t = Math.cos(vars.frameNo / 300) / 165
vars.camX = Math.sin(p + t) * d
vars.camZ = Math.cos(p + t) * d
vars.camY = -Math.sin(vars.frameNo / 220) * 15
vars.yaw = Math.PI + p + t
vars.pitch = elevation(vars.camX, vars.camZ, vars.camY) - Math.PI / 2
var t
for(var i=0i<vars.points.length++i){
x=vars.points[i].x
y=vars.points[i].y
z=vars.points[i].z
d=Math.sqrt(x*x+z*z)/1.0075
t=.1/(1+d*d/5)
p=Math.atan2(x,z)+t
vars.points[i].x=Math.sin(p)*d
vars.points[i].z=Math.cos(p)*d
vars.points[i].y+=vars.points[i].vy*t*((Math.sqrt(vars.distributionRadius)-d)*2)
if(vars.points[i].y>vars.vortexHeight/2 || d<.25){
vars.points.splice(i,1)
spawnParticle(vars)
}
}
}
function drawFloor(vars){
var x,y,z,d,point,a
for (var i = -25i <= 25i += 1) {
for (var j = -25j <= 25j += 1) {
x = i*2
z = j*2
y = vars.floor
d = Math.sqrt(x * x + z * z)
point = project3D(x, y-d*d/85, z, vars)
if (point.d != -1) {
size = 1 + 15000 / (1 + point.d)
a = 0.15 - Math.pow(d / 50, 4) * 0.15
if (a >0) {
vars.ctx.fillStyle = colorString(interpolateColors(rgbArray(d/26-vars.frameNo/40),[0,128,32],.5+Math.sin(d/6-vars.frameNo/8)/2))
vars.ctx.globalAlpha = a
vars.ctx.fillRect(point.x-size/2,point.y-size/2,size,size)
}
}
}
}
vars.ctx.fillStyle = "#82f"
for (var i = -25i <= 25i += 1) {
for (var j = -25j <= 25j += 1) {
x = i*2
z = j*2
y = -vars.floor
d = Math.sqrt(x * x + z * z)
point = project3D(x, y+d*d/85, z, vars)
if (point.d != -1) {
size = 1 + 15000 / (1 + point.d)
a = 0.15 - Math.pow(d / 50, 4) * 0.15
if (a >0) {
vars.ctx.fillStyle = colorString(interpolateColors(rgbArray(-d/26-vars.frameNo/40),[32,0,128],.5+Math.sin(-d/6-vars.frameNo/8)/2))
vars.ctx.globalAlpha = a
vars.ctx.fillRect(point.x-size/2,point.y-size/2,size,size)
}
}
}
}
}
function sortFunction(a,b){
return b.dist-a.dist
}
function draw(vars){
vars.ctx.globalAlpha=.15
vars.ctx.fillStyle="#000"
vars.ctx.fillRect(0, 0, canvas.width, canvas.height)
drawFloor(vars)
var point,x,y,z,a
for(var i=0i<vars.points.length++i){
x=vars.points[i].x
y=vars.points[i].y
z=vars.points[i].z
point=project3D(x,y,z,vars)
if(point.d != -1){
vars.points[i].dist=point.d
size=1+vars.points[i].radius/(1+point.d)
d=Math.abs(vars.points[i].y)
a = .8 - Math.pow(d / (vars.vortexHeight/2), 1000) * .8
vars.ctx.globalAlpha=a>=0&&a<=1?a:0
vars.ctx.fillStyle=rgb(vars.points[i].color)
if(point.x>-1&&point.x<vars.canvas.width&&point.y>-1&&point.y<vars.canvas.height)vars.ctx.fillRect(point.x-size/2,point.y-size/2,size,size)
}
}
vars.points.sort(sortFunction)
}
function spawnParticle(vars){
var p,ls
pt={}
p=Math.PI*2*Math.random()
ls=Math.sqrt(Math.random()*vars.distributionRadius)
pt.x=Math.sin(p)*ls
pt.y=-vars.vortexHeight/2
pt.vy=vars.initV/20+Math.random()*vars.initV
pt.z=Math.cos(p)*ls
pt.radius=200+800*Math.random()
pt.color=pt.radius/1000+vars.frameNo/250
vars.points.push(pt)
}
function frame(vars) {
if(vars === undefined){
var vars={}
vars.canvas = document.querySelector("canvas")
vars.ctx = vars.canvas.getContext("2d")
vars.canvas.width = document.body.clientWidth
vars.canvas.height = document.body.clientHeight
window.addEventListener("resize", function(){
vars.canvas.width = document.body.clientWidth
vars.canvas.height = document.body.clientHeight
vars.cx=vars.canvas.width/2
vars.cy=vars.canvas.height/2
}, true)
vars.frameNo=0
vars.camX = 0
vars.camY = 0
vars.camZ = -14
vars.pitch = elevation(vars.camX, vars.camZ, vars.camY) - Math.PI / 2
vars.yaw = 0
vars.cx=vars.canvas.width/2
vars.cy=vars.canvas.height/2
vars.bounding=10
vars.scale=500
vars.floor=26.5
vars.points=[]
vars.initParticles=700
vars.initV=.01
vars.distributionRadius=800
vars.vortexHeight=25
}
vars.frameNo++
requestAnimationFrame(function() {
frame(vars)
})
process(vars)
draw(vars)
}
frame()
</script>
</body>
</html>
