<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>打印九九乘法表</title> </head> <body> <script> document.write('<table border="1" style="border-collapse:collapse">') for (var i = 1; i <= 9; i++) { document.write('<tr>') for (var j = 1; j <= i; j++) { document.write('<td>' + j + '*' + i + '=' + i * j + '</td>') } document.write('</tr>') } document.write('</table>') </script> </body> </html>
js代码（打印三角形）
<script>
//正的直角三角形
for (var i = 1; i <= 9; i++) {
for (var j = 1; j <= i; j++) {
document.write('★ ');
}
document.write('<br/>');
}
document.write('<br/>');
document.write('<br/>');
document.write('<br/>');
// 倒的直角三角形
// 循环的次数，for会一次执行完成
for (var i = 1; i <= 9; i++) {
// 每行的个数
for (var j = i; j <= 9; j++) {
document.write('★ ');
}
document.write('<br/>');
}
</script>
数组冒泡排序
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>数组冒泡排序</title>
</head>
<body>
<script>
var arr = [2, 5, 12, 21, 54, 22, 61, 6, 1, 72, 4, 1, 3, 5, 3, 51, 4, 2, 22]
// 外层循环控制比较的轮数（length-1）
for (var i = 0; i < arr.length - 1; i++) {
// 外层循环控制比较的次数
for (var j = 0; j < arr.length - 1 - i; j++) {
// 比较大小看前一项是否大于后一项
if (arr[j] > arr[j + 1]) {
// 为true交互两个的值
var temp = arr[j]
arr[j] = arr[j + 1]
arr[j + 1] = temp
}
}
}
console.log(arr)
</script>
</body>
</html>