19JS输出杨辉三角
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
</head>
<body>
<script>
function print(v) {
if (typeof v == "number") {
var w = 30;
if (n > 30) w = n - 30 + 40;
var s =
'<span style="padding:4px 2px;display:inline-block;text-align:center;width:' +
w +
'px;">' +
v +
"</span>";
document.write(s);
} else {
document.write(v);
}
}
var n = prompt("请输入幂数：", 9);
n = n - 0;
var t1 = new Date();
var a1 = [1, 1];
var a2 = [1, 1];
print('<div style=text-align:center;">');
for (var i = 0; i <= n; i++) {
for (var j = 1; j < i + 2; j++) {
print(c(i, j));
}
print("<br />");
}
print("</div>");
var t2 = new Date();
print(
"<p style='text-align:center;'>耗时为（毫秒）：" + (t2 - t1) + "</p>"
);
function c(x, y) {
if (y == 1 || y == x + 1) return 1;
return c(x - 1, y - 1) + c(x - 1, y);
}
</script>
</body>
</html>
