for循环
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>首页</title>
</head>
<body>
<script type="text/javascript">
var num = 100
for (let i = 0; i < num; i++){
console.log(i)
}
</script>
</body>
</html>
循环嵌套，如果要将结果打印在页面上使用 document.write
while循环
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>首页</title>
</head>
<body>
<script type="text/javascript">
let i = 0
while(i <= 10){
document.write(i + "<br>")
i ++
}
</script>
</body>
</html>
break和continue
break和continue都有跳出语句的功能。break是跳出整个循环，continue是跳出当前本次循环。
当i的值为3的时候就跳出循环，这个循环就结束了。
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>首页</title>
</head>
<body>
<script type="text/javascript">
for(let i = 1; i <= 10; i++){
if (i == 5){
document.write("本次循环结束" + "<br>")
continue
}
document.write(i + "<br>")
}
</script>
</body>
</html>
