為什么彈窗會(huì)出來(lái)兩次??？
<!DOCTYPE? HTML>
<html >
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>數(shù)組</title>
<script type="text/javascript">
?//創(chuàng)建數(shù)組
?var? arr = ['*','##',"***","&&","****","##*"];
? ?arr[7] = "**";
?//顯示數(shù)組長(zhǎng)度
?alert("長(zhǎng)度："+arr.length);
?
?//將數(shù)組內(nèi)容輸出，完成達(dá)到的效果。
for(var i=0;i<arr.length;i++)
{
? ? document.write(arr[i]+'<br>');
}
</script>
</head>
<body>
</body>
</html>
2019-05-07
???什么意思