<!DOCTYPE HTML>
<html >
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>数组</title>
<script type="text/javascript">
var myarr=['*','**','***','****'];
var length=myarr.length;
for(var i=0;i<length;i++)
document.write(myarr[i]+"</br>");
</div>
function showLen()
{
alert("数组长度为"+length);
}
//将数组内容输出,完成达到的效果。
</script>
</head>
<body>
<form>
<input type="button" onclick="showLen()" value="数组的长度">
</form>
</body>
</html>
你代码里13行有错误,多了个‘</div>’,我给你改了,另外我自己写的实现不知道符合你的需求不。
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>数组</title>
<script type="text/javascript">
var myarr = ['*', '**', '***', '****'];
var length = myarr.length;
for (var i = 0; i < length; i++) {
document.write('<span>' + myarr[i] + "</br></span>");
}
function showLen() {
alert("数组长度为" + length);
}
setTimeout(function() {
var d = document;
var s = true;
var spans = d.querySelectorAll('span');
var f = d.querySelector('form');
var btn = d.createElement('input');
btn.setAttribute('type', 'button');
btn.setAttribute('value', '清除/显示');
f.appendChild(btn);
btn.addEventListener('click', function() {
if (s == true) {
for (var i = 0; i < spans.length; i++) {
spans[i].style.display = 'none';
}
s = !s;
} else {
for (var i = 0; i < spans.length; i++) {
spans[i].style.display = 'block';
}
s = !s;
}
})
}, 300);
</script>
</head>
<body>
<form>
<input type="button" onclick="showLen()" value="数组的长度">
</form>
</body>
</html>