1，打印1-100之間所有奇數之和
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>打印1-100之間所有奇數之和</title>
<script type="text/javascript">
var sum=0;
for (var i = 1; i <=100; i++) {
if (i % 2 != 0) {
sum += i
}
}
alert(sum);
</script>
</head>
<body>
</body>
</html>
2.1-100之間所有7的倍數個數及和
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>1-100之間所有7的倍數個數及和</title>
<script type="text/javascript">
var list = [];
var sum = 0;
for (var i = 1; i <= 100; i++) {
if (i % 7 == 0) {
list.push(i)
sum+=i
}
}
alert(list.length + 1);
alert(sum);
</script>
</head>
<body>
</body>
</html>
3.水仙花數
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>水仙花數</title>
<script type="text/javascript">
var gw,sw,bw;
for (var i = 100; i <= 999; i++) {
bw = parseInt(i / 100);
sw = parseInt((i / 10) % 10);
gw = parseInt(i % 10);
if (i == bw*bw*bw + sw*sw*sw + gw*gw*gw) {
document.write(i + '是水仙花數' + '<br />');
}
}
</script>
</head>
<body>
</body>
</html>
4.判斷是否為質數
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>判斷是否為質數</title>
<script type="text/javascript">
if(num<=1||isNaN(num)){
alert('請正確輸入！')
}else{
var flag = true;
for(var i = 2;i<num;i++){
if(num % i ==0){
flag = false;
}
}
if(flag){
alert('是質數');
}
}
</script>
</head>
<body>
</body>
</html>
5.九九乘法表
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>九九乘法表</title>
<script type="text/javascript">
for (var n = 1; n <= 9; n++) {
for (var m = 1;m <=9; m++) {
var b = m*n;
document.write('' + m + '*' + n + '=' + b + ' ');
}
document.write('<br/>');
}
</script>
</head>
<body>
</body>
</html>
while循環
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>while循環_</title>
<script type="text/javascript">
// 1、假如投資的年利率為5%，試求從1000塊增長到5000塊，需要花費多少年
// 1000 1000+10000.05=10001.05
// 1050 1050+10500.05=10501.05
// ……
// 5000
var money = 1000;
var count = 0;
while(money <= 5000){
money*=1.05;
count++;
}
console.log(count)
</script>
</head>
<body>
</body>
</html>
