# Javascript disk raffle program implementation principle and complete code examples

• 2020-03-30 03:07:43
• OfStack

Effect preview:

< img SRC = "border = 0 / / img.jbzj.com/file_images/article/201406/20146394819279.png? 20145394926 ">

One, simulate the realization process of lucky draw

Run method, the argument Angle refers to the Angle

``````
function run(angle) {
if (isIE) {
cosDeg = Math.cos(angle * Math.PI / 180);
sinDeg = Math.sin(angle * Math.PI / 180);
with (target.filters.item(0)) {
M11 = M22 = cosDeg; M12 = -(M21 = sinDeg);
}
target.style.top = (orginH - target.offsetHeight) / 2 + "px";
target.style.left = (orginW - target.offsetWidth) / 2 + "px";
} else if (target.style.MozTransform !== undefined) {
target.style.MozTransform = "rotate(" + angle + "deg)";
} else if (target.style.OTransform !== undefined) {
target.style.OTransform = "rotate(" + angle + "deg)";
} else if (target.style.webkitTransform !== undefined) {
target.style.webkitTransform = "rotate(" + angle + "deg)";
} else {
target.style.transform = "rotate(" + angle + "deg)";
}
}``````

Analog turntable acceleration, uniform and deceleration. When the Angle is less than a certain value, the coefficient of 1.01 is used as the acceleration. When the Angle is greater than a certain value, it is in the state of high speed and uniform speed. When the Angle is greater than the set maximum value, the coefficient of 0.99 is used to slow it down. Set a negative number as the value of deceleration (that is, the variable TMP), then get the value in the negative 360 (that is, the variable m), when greater than this value, the turntable stops.
``````
var tmp = -900;
var m = -parseInt(Math.random() * 360);
timer = setInterval(function () {
if (i > 3000) {
tmp = parseInt(tmp * 0.99);
if (tmp > m) {
tmp = m;
clearInterval(timer);
msg(m);
}
run(tmp);
}
else if (i > 1000) {
i = i + 45;
run(i);
}
else {
i = parseInt((i + 1) * 1.01);
run(i);
}
}, 50);``````

Start the draw and reset the draw
``````
<input id="test" type="button" value=" Lucky draw " />
<input id="restart" style="display: none;" type="button" value=" Smoke once again " />
m\$('test').onclick = function () {
m\$('test').style.display = "none";
showMsg();
}
m\$('restart').onclick = function () {
m\$('restart').style.display = "none";
if (isIE) {
m\$("demo").style.top = "0px";
m\$("demo").style.left = "0px";
} else if (m\$("demo").style.MozTransform !== undefined) {
m\$("demo").style.MozTransform = 'rotate(0deg)';
} else if (m\$("demo").style.OTransform !== undefined) {
m\$("demo").style.OTransform = 'rotate(0deg)';
} else if (m\$("demo").style.webkitTransform !== undefined) {
m\$("demo").style.webkitTransform = 'rotate(0deg)';
} else {
m\$("demo").style.transform = 'rotate(0deg)';
}
m\$('test').style.display = "block";
i = 0;
}``````

Ii. Complete code demo:

``````<!DOCTYPE html>
<html>
<title> Lucky draw </title>
<style type="text/css">
#container{width: 400px;height: 400px;position: relative;margin: 0 auto;}
#demo{position: absolute;filter: progid:DXImageTransform.Microsoft.Matrix(sizingmethod="auto expand");}
</style>
<body style="height: 1000px;">
<div id="container">
<div id="demo">
<img alt="" src="//img.jbzj.com/file_images/article/201406/20146394819279.png?20145394926" width="400" height="400" />
</div>
</div>
<input id="test" type="button" value=" Lucky draw " />
<input id="restart" style="display: none;" type="button" value=" Smoke once again " />
<div id="msg">
</div>
<script type="text/javascript">
var m\$ = function (id) { return document.getElementById(id); }
var ua = navigator.userAgent;
var isIE = /msie/i.test(ua) && !window.opera;
var i = 1, sinDeg = 0, cosDeg = 0, timer = null;
var mRotate = function () {
var rotate = function (target, msg) {
target = m\$(target);
var orginW = target.clientWidth, orginH = target.clientHeight;
clearInterval(timer);
function run(angle) {
if (isIE) {
cosDeg = Math.cos(angle * Math.PI / 180);
sinDeg = Math.sin(angle * Math.PI / 180);
with (target.filters.item(0)) {
M11 = M22 = cosDeg; M12 = -(M21 = sinDeg);
}
target.style.top = (orginH - target.offsetHeight) / 2 + "px";
target.style.left = (orginW - target.offsetWidth) / 2 + "px";
} else if (target.style.MozTransform !== undefined) {
target.style.MozTransform = "rotate(" + angle + "deg)";
} else if (target.style.OTransform !== undefined) {
target.style.OTransform = "rotate(" + angle + "deg)";
} else if (target.style.webkitTransform !== undefined) {
target.style.webkitTransform = "rotate(" + angle + "deg)";
} else {
target.style.transform = "rotate(" + angle + "deg)";
}
}
var tmp = -900;
var m = -parseInt(Math.random() * 360);
timer = setInterval(function () {
if (i > 3000) {
tmp = parseInt(tmp * 0.99);
if (tmp > m) {
tmp = m;
clearInterval(timer);
msg(m);
}
run(tmp);
}
else if (i > 1000) {
i = i + 45;
run(i);
}
else {
i = parseInt((i + 1) * 1.01);
run(i);
}
}, 50);
}
return { rotate: rotate }
} ();
function showMsg() {
mRotate.rotate("demo", function msg(m) {
if (m > -90 && m < -30) {
m\$("msg").innerHTML += "22222222";
}
else if (m > -150 && m < -90) {
m\$("msg").innerHTML += "333333333";
}
else if (m > -210 && m < -150) {
m\$("msg").innerHTML += "444444";
}
else if (m > -270 && m < -210) {
m\$("msg").innerHTML += "5555555";
}
else if (m > -330 && m < -270) {
m\$("msg").innerHTML += "6666666";
} else {
m\$("msg").innerHTML += "111111111";
}
m\$('restart').style.display = "block";
});
}
m\$('test').onclick = function () {
m\$('test').style.display = "none";
showMsg();
}
m\$('restart').onclick = function () {
m\$('restart').style.display = "none";
if (isIE) {
m\$("demo").style.top = "0px";
m\$("demo").style.left = "0px";
} else if (m\$("demo").style.MozTransform !== undefined) {
m\$("demo").style.MozTransform = 'rotate(0deg)';
} else if (m\$("demo").style.OTransform !== undefined) {
m\$("demo").style.OTransform = 'rotate(0deg)';
} else if (m\$("demo").style.webkitTransform !== undefined) {
m\$("demo").style.webkitTransform = 'rotate(0deg)';
} else {
m\$("demo").style.transform = 'rotate(0deg)';
}
m\$('test').style.display = "block";
i = 0;
}
}
</script>
</body>
</html>``````

Related articles: