奇數(shù)之和
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>奇數(shù)之和</title>
<script type="text/javascript">
for(var i=1,sum=0; i<=100; i++){
if(i % 2 != 0){
sum += i;
}
}
console.log("奇數(shù)之和為：" + sum);
</script>
</head>
<body>
</body>
</html>
7的倍數(shù)
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>7的倍數(shù)</title>
<script type="text/javascript">
var sum = 0;
var count = 0;
for(var i=1; i<=100; i++){
if (i % 7 == 0) {
sum += i;
count++;
}
}
console.log("總和為：" + sum);
console.log("個數(shù)為：" + count);
</script>
</head>
<body>
</body>
</html>
水仙花數(shù)
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>水仙花數(shù)</title>
<script type="text/javascript">
for(var i=100; i<1000; i++){
var b = parseInt(i/100);
var s = parseInt((i-b*100)/10);
var g = i % 10;
if(b**3 + s**3 + g**3 == i){
console.log(i);
}
}
</script>
</head>
<body>
</body>
</html>
判斷是否為質(zhì)數(shù)
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>判斷是否為質(zhì)數(shù)</title>
<script type="text/javascript">
var num = prompt("請輸入一個大于1的整數(shù)：");
if(num <= 1 || isNaN(num)){
alert('該值不合法！');
}else{
var flag = true;
for(var i=2; i<num; i++){
if(num % i ==0){
flag = false;
}
}
if(flag){
alert(num + "是質(zhì)數(shù)！");
}else{
alert(num + "不是質(zhì)數(shù)！");
}
}
</script>
</head>
<body>
</body>
</html>
99乘法表
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<html lang="en">
<head>
<meta charset="UTF-8">
<title>99乘法表</title>
<style type="text/css">
body{
width: 1000px;
}
span{
display: inline-block;
width: 70px;
}
</style>
<script type="text/javascript">
for(var i=1; i<=9; i++){
for(var j=1; j<=i; j++){
document.write("<span>"+j+"*"+i+"="+i*j+"</span>");
}
document.write('<br>');
}
</script>
</head>
<body>
</body>
</html>
1~100之間的質(zhì)數(shù)
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>1-100之間所有的質(zhì)數(shù)</title>
<script type="text/javascript">
console.time("test");
for(var i=2; i<=100; i++){
var flag = true;
for(var j=2; j<=Math.sqrt(i); j++){
if(i % j ==0){
flag = false;
break;
}
}
if(flag){
console.log(i);
}
}
console.timeEnd("test");
</script>
</head>
<body>
</body>
</html>
