<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<script>
//do-while
function sum1(){
var r1=0;
var i=0;
do{
i++;
r1 +=i;
}
while(i<=100);
return r1
}
alert(sum1())
//while
function sum2(){
var r2=0;
var i=0;
while(i<=100){
i++;
r2 += i;
}
return r2
}
alert(sum2())
//for 循环
function sum(){
var result =0;
for(var i=0;i<=100; i++){
result += i;
}
return result
}
var c =sum();
alert(c);
</script>
</body>
</html>