这样应该是正确的吧
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>增加新元素</title>
<script language="javascript">
var myarray=new Array();
myarray[0]=88;
myarray[1]=90;
myarray[2]=68;
myarray[3]=99;
document.write("数组第一个值是:"+myarray[0]+"<br>");
document.write("数组第二个值是:"+myarray[1]+"<br>");
document.write("数组第三个值是:"+myarray[2]+"<br>");
document.write("数组第四个值是:"+myarray[3]+"<br>");
</script>
</head>
<body>
</body>
</html>
