Js and html5 to achieve the phone side scratch card lottery effect perfect compatibility with android and IOS

2020-03-29 23:52:17
OfStack

It's definitely worth reading, haha. I personally completed, there are errors please point out:
Now the mobile phone supports html5 perfectly, so if the mobile phone wants to do a lucky draw module, using scratch card lucky draw effect, believe that this interactive experience is very good
The & # 8203; Ps: because I do not have a phone with wp8 system,I cannot be compatible with wp8 system. Now it is perfectly compatible with android and IOS
If you want to browse in the PC, you have to change js, currently support Google, firefox, ie> =10, if the net friend wants, I will write one
The code is as follows:

 
<!DOCTYPE html> 
<html lang="en"> 
<head> 
<meta charset="UTF-8" /> 
<meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0" /> 
<title>eraser effect</title> 
<script type="text/javascript" src="jquery.core.js"></script> 
<style> 
#canvas { 
background:url(winning-ticket.jpg);<!-- The prize images --> 
width: 531px; 
height: 438px; 
} 
.before{ 
background:none !important; 
} 
#canvas canvas { 
cursor: url("hand.png") 0 0, auto;<!--PC End gesture picture --> 
} 
</style> 
</head> 
<body oncontextmenu="return false;" onselectstart="return false;"> 
<div id="canvas"></div> 
</body> 
<script type="text/javascript"> 
(function() { 
window.onload = function(){ 
 
try{ 
document.createElement('canvas').getContext('2d'); 
}catch(e){ 
var addDiv = document.createElement('div'); 
alert(' Your mobile phone does not support scratch card effect oh ~!'); 
} 
}; 
var u = navigator.userAgent,mobile = ''; 
if(u.indexOf('iPhone') > -1) mobile = 'iphone'; 
if(u.indexOf('Android') > -1 || u.indexOf('Linux') > -1) mobile = 'Android'; 
function createCanvas(parent, width, height) { 
var canvas = {}; 
canvas.node = document.createElement('canvas'); 
canvas.context = canvas.node.getContext('2d'); 
canvas.node.width = width || 100; 
canvas.node.height = height || 100; 
parent.appendChild(canvas.node); 
return canvas; 
} 
function init(container, width, height, fillColor, type) { 
var canvas = createCanvas(container, width, height); 
var ctx = canvas.context; 
// define a custom fillCircle method 
ctx.fillCircle = function(x, y, radius, fillColor) { 
this.fillStyle = fillColor; 
this.beginPath(); 
this.moveTo(x, y); 
this.arc(x, y, radius, 0, Math.PI * 2, false); 
this.fill(); 
}; 
ctx.clearTo = function(fillColor) { 
ctx.fillStyle = fillColor; 
ctx.fillRect(0, 0, width, height); 
}; 
ctx.clearTo(fillColor || "#ddd"); 
canvas.node.addEventListener("touchstart",function(e){ 
canvas.isDrawing = true; 
},false); 
canvas.node.addEventListener("touchend",function(e){ 
canvas.isDrawing = false; 
},false); 
canvas.node.addEventListener("touchmove",function(e){ 
if (!canvas.isDrawing) { 
return; 
} 
if(type == 'Android'){ 
var x = e.changedTouches[0].pageX - this.offsetLeft; 
var y = e.changedTouches[0].pageY - this.offsetTop; 
}else{ 
var x = e.pageX - this.offsetLeft; 
var y = e.pageY - this.offsetTop; 
} 
var radius = 20; 
var fillColor = '#ff0000'; 
ctx.globalCompositeOperation = 'destination-out'; 
ctx.fillCircle(x, y, radius, fillColor); 
},false); 
} 
var container = document.getElementById('canvas'); 
init(container, 531, 438, '#ff0000', mobile); 
})(); 
</script> 
</html>