這種方式簡潔，快捷
<!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=[88,90,68];
myarray[myarray.length] = 99;
?document.write("數組第一個值是:"+myarray[0]+"<br>");
?document.write("數組第二個值是:"+myarray[1]+"<br>");
?document.write("數組第三個值是:"+myarray[2]+"<br>");
document.write("數組第三個值是:"+myarray[3]+"<br>");
</script>
</head>
<body>
</body>
</html>
2020-06-18
不用減1吧，直接[length]就行
2019-07-06
myarray[myarray.length-1]=99;
2019-06-19
656