//1 .for循环
var result = 0;
for (var i = 0; i <= 100; i++) {
result += i;
}
document.write(result);
document.write("<br />");
//2. while()循环
var result2 = 0;
var i = 0;
while (i <= 99) {
i++;
result2 += i;
}
document.write(result2);
document.write("<br />");
// do-while语句
var result3 = 0;
var i = 0;
do {
i++;
result3 += i;
}
while (i <= 99);
document.write(result3)
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<script>
</script>
</head>
<body>
<script>
</script>
</body>
</html>