为什么出现两次图形
<!DOCTYPE HTML>
<html >
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>数组</title>
<script type="text/javascript">
//创建数组
var arr= ['*','##',"***","&&","****","##*"];
arr[7] = "**";
//显示数组长度
alert(arr.length);
//将数组内容输出，完成达到的效果。
document.write(arr[0]+"<br/>");
document.write(arr[7]+"<br/>");
document.write(arr[2]+"<br/>");
document.write(arr[4]+"<br/>");
</script>
</head>
<body>
</body>
</html>
