<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style type="text/css">
*{margin: 0;padding: 0;}
div{font-size: 60px;position: absolute;}
</style>
</head>
<body>
<h2 id="score">得分：0</h2>
</body>
</html>
<script>
var timer=null;
setInterval(function(){
var div=document.createElement("div");
var n=String.fromCharCode(parseInt(65+Math.random()*26));
div.innerText=n;
div.style.top=0;
div.style.left=parseInt(200+Math.random()*900)+"px";
document.body.appendChild(div);
move(div)
},1000) //设置再页面顶部随机出现字母
function move(obj){
setInterval(function(){
var speed=2;
if(obj.offsetTop>500){
obj.remove();
}
obj.style.top=obj.offsetTop+speed+"px";
},30)
} //设置往下掉的速度 每30MS下掉2PX
var oScore=document.getElementById("score");
var num=0;
document.onkeypress=function(e){
var aDiv=document.getElementsByTagName("div")
var e=e||event;
var code=e.keyCode||e.which;
for(i=0;i<aDiv.length;i++){
var code1=aDiv[i].innerText.charCodeAt(0);
if(code1==code){
num++;
aDiv[i].remove();
oScore.innerText="得分"+num;
break;
}
}
}
</script>