javascript 循环 while ，for ，switch ，do..while,for ..in

循环实例：
<!--do...while循环-->
<script>
do {
var input = prompt('How are you')
} while (!input);
</script>

<!--for循环获取所有的偶数-->
<script>
for (var number = 0; number <= 12; number += 2) {
document.write(number + '<br/>');
}
</script>
<script>
var count = 1;
for (var result = 0; result < 10; result += 1) {
count = count * 2
}
alert(count)
</script>

<script>
//switch 循环
switch (prompt("what it you name")) {
case "tim":
document.write('my name is tim');
break;
case 'sunny':
document.write("my name is sunny");
break;
default :
document.write('Unknow weather type!');
break;
}
</script>
for..in循环...
<script>
var k = [1,2,3,4,5];
for(var i in k){
console.log(i);
}
</script>
建议不使用，应为他要访问原型，如果确实需要使用for....in循环，建议控制到访问当前
<script>
var k = [1,2,3,4,5];

for(var i in k){

//code from http://caibaojian.com/js-loop-for-in.htmlif(array.hasOwnProperty(i)){result.push(array[i]);} }
</script>