1. 设置定时器
语法：setInterval(函数，时间)
注意：
函数书写时不能带括号
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setInterval(fn,1000)//正确
setInterval(fn(),1000)//错误
时间的最小设置不小于14ms
2. 清除定时器
语法：clearInterval(所清除的定时器名称)
3. 实例探究
js部分
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window.onload = function() {
var timer = null;
var num = 0;
var i = 0;
var arr=['red','#FF9D0C','#DBFF0D','#3BFF0D','#0DFFA2','#0DE8FF','#0D52FF','#210DFF','#930DFF','#FF0DB4']
var start = document.getElementById('start');
var stop = document.getElementById('stop');
var prizeDraw = document.getElementById('prizeDraw');
start.onclick = function() {
clearInterval(timer);
timer = setInterval(function(){
num = Math.floor(Math.random()*100+1);
prizeDraw.style.backgroundColor = arr[i];
i++;
if (i==9) {
i = 0;
};
prizeDraw.innerHTML = num;
},100);
}
stop.onclick = function() {
clearInterval(timer);
}
}
css部分
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#prizeDraw {
width: 100px;
height: 100px;
background: rgba(255,68,253,0.5);
font-size: 30px;
text-align: center;
line-height: 100px;
}
