while 

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>范例5-7</title>
</head>
<body>
<script language="javascript">
    var num = 1;
    while( num < 101 )
    {
        document.write( num + " " );
        num++;
    }
</script>
</body>
</html>

 

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>范例5-8</title>
</head>
<body>
<script language="javascript">
    var num = 1;
    do
    {
        document.write( num + " " );
        num++;
    }
    while( num < 101 )
</script>
</body>
</html>

 

 

while ...break

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>范例5-9</title>
</head>
<body>
<script language="javascript">
    var time = 0;  
    while( true )                                               // 无限循环
    {
        time++;
        var random  = Math.floor( Math.random() * (1000) );     // 摇奖，随机产生2位中奖号码
        if( random == 352 )                                     // 这位彩票迷的号为：35
        {
           alert( "恭喜你，偿试了" + time + "遍，终于中了一次奖（号码：352）"); 
           break;
        }
    }
</script>
</body>
</html>

 

posted on 2017-08-09 21:26  huodaihao  阅读(124)  评论(0)  编辑  收藏  举报

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