console 命令行工具 X clear

console

var n = 1;
var sum = 0;
//如果n小于等于100，则会执行while循环
while (n <= 100)
{
sum=sum+n;
n=n+1;
}
document.write("1+2+3+…+100 = " + sum);
document.write('<br/>---------------------------------<br/>');

var n = 1;
var sum = 0;
do
{
sum += n;
n++;
}while (n <= 100);
document.write("1+2+3+…+100 = " + sum);
document.write('<br/>---------------------------------<br/>');

for(var i=0;i<101;i++ ){}
document.write("1+2+3+…+100 = " + sum);
document.write('<br/>---------------------------------<br/>');

<!DOCTYPE html> 
<html>
<head>
    <meta charset="utf-8" />
    <title></title>
    <script>
      
    </script>
</head>
<body>
</body>
</html>