console 命令行工具 X clear

console

//方法1：while循环
var n = 1;
var sum = 0;
while (n <= 100){
    sum = sum + n;
    n++;

}
document.write("方法1：while循环--------------" + "<br/>");
document.write("1+2+3+…+100 = " + sum + "<br/>");
document.write("<br/>");

//方法2：do while循环
var n1 = 1;
var sum1 = 0;
do{
    sum1 = sum1+n1;
    n1++;
}while (n1 <= 100);
document.write("方法2：do while循环----------" + "<br/>");
document.write("1+2+3+…+100 = " + sum1 + "<br/>");
document.write("<br/>");

//方法3：for循环
var sum2 = 0;
for(var n2=0;n2<=100;n2++){
    sum2 =sum2 + n2;
}
document.write("方法3：for循环----------------" + "<br/>");
document.write("1+2+3+…+100 = " + sum2 + "<br/>");
document.write("<br/>");

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