我正在尝试保留id＆＃34; bestTime＆＃34;下的最佳时间值，但我继续在Chrome中收到以下错误：无法读取属性＆inner;内部HTML＆＃39;在showBestTime上为null。
不确定我做错了什么，我附上了以下代码。我正在尝试处理函数showBestTime中的最佳时间。提前谢谢！
<html>
<head>
<title>Reaction tester</title>
</head>
<style type="text/css">
#page-container{
width: 1000px;
margin: 0 auto;
height: 800px;
}
body{
margin: 0;
padding: 0;
font-family: Helvetica, Arial, freesans, sans-serif;
}
#shape{
width: 200px;
height: 200px;
background-color: red;
display: none;
position: relative;
}
.time{
font-weight: bold;
}
</style>
<body>
<div id="page-container">
<h1>Test Your Reactions!</h1>
<p>Click on the boxes and circles as quickly as you can!</p>
<p class="time">Your time: <span id="timeTaken"></span></p>
<p class="time">Best time: <span id="bestTime">10</span>s</p>
<div id="shape"></div>
</div>
<script type="text/javascript">
var start=new Date().getTime();
function getRandomColor() {
var letters= "0123456789ABCDEF";
var color= "#";
for (var i=0; i<6; i++) {
color +=letters[Math.floor(Math.random()*16)];
}
return color;
}
function makeShapeAppear(){
var top=Math.random()*400;
var left=Math.random()*800;
var width=(Math.random()*400)+100;
if(Math.random()>0.5){ document.getElementById("shape").style.borderRadius="50%";
} else{
document.getElementById("shape").style.borderRadius="0";
} document.getElementById("shape").style.backgroundColor=getRandomColor();
document.getElementById("shape").style.top=top+"px";
document.getElementById("shape").style.left=left+"px"; document.getElementById("shape").style.width=width+"px"; document.getElementById("shape").style.height=width+"px";
document.getElementById("shape").style.display="block";
start=new Date().getTime();
}
function appearAfterDelay(){
setTimeout(makeShapeAppear, (Math.random() * 2000));
}
function showBestTime(y){ if(y<document.getElementById("besttime").innerHTML){
document.getElementById("besttime").innerHTML=y;
}
}
appearAfterDelay();
document.getElementById("shape").onclick=function(){
document.getElementById("shape").style.display="none";
var end=new Date().getTime();
var timeTaken=(end-start)/1000; document.getElementById("timeTaken").innerHTML=timeTaken+"s";
appearAfterDelay();
showBestTime(timeTaken);
}
</script>
</body>
</html>
答案 0 :(得分：1)
您在选择器中犯了拼写错误。您已将besttime作为选择器而不是bestTime。我已经添加了工作代码。
<html>
<head>
<title>Reaction tester</title>
</head>
<style type="text/css">
#page-container {
width: 1000px;
margin: 0 auto;
height: 800px;
}
body {
margin: 0;
padding: 0;
font-family: Helvetica, Arial, freesans, sans-serif;
}
#shape {
width: 200px;
height: 200px;
background-color: red;
display: none;
position: relative;
}
.time {
font-weight: bold;
}
</style>
<body>
<div id="page-container">
<h1>Test Your Reactions!</h1>
<p>Click on the boxes and circles as quickly as you can!</p>
<p class="time">Your time: <span id="timeTaken"></span></p>
<p class="time">Best time: <span id="bestTime">10</span>s</p>
<div id="shape"></div>
</div>
<script type="text/javascript">
var start = new Date().getTime();
function getRandomColor() {
var letters = "0123456789ABCDEF";
var color = "#";
for (var i = 0; i < 6; i++) {
color += letters[Math.floor(Math.random() * 16)];
}
return color;
}
function makeShapeAppear() {
var top = Math.random() * 400;
var left = Math.random() * 800;
var width = (Math.random() * 400) + 100;
if (Math.random() > 0.5) {
document.getElementById("shape").style.borderRadius = "50%";
} else {
document.getElementById("shape").style.borderRadius = "0";
}
document.getElementById("shape").style.backgroundColor = getRandomColor();
document.getElementById("shape").style.top = top + "px";
document.getElementById("shape").style.left = left + "px";
document.getElementById("shape").style.width = width + "px";
document.getElementById("shape").style.height = width + "px";
document.getElementById("shape").style.display = "block";
start = new Date().getTime();
}
function appearAfterDelay() {
setTimeout(makeShapeAppear, (Math.random() * 2000));
}
function showBestTime(y) {
if (y < document.getElementById("bestTime").innerHTML) {
document.getElementById("bestTime").innerHTML = y;
}
}
appearAfterDelay();
document.getElementById("shape").onclick = function () {
document.getElementById("shape").style.display = "none";
var end = new Date().getTime();
var timeTaken = (end - start) / 1000;
document.getElementById("timeTaken").innerHTML = timeTaken + "s";
appearAfterDelay();
showBestTime(timeTaken);
}
</script>
</body>
</html>
答案 1 :(得分：0)
你有跨度：
<span id="bestTime">
并使用
进行查询document.getElementById("besttime")
且bestTime不等于besttime，因此请更改为：
document.getElementById("bestTime")