2.13.JavaScript--条件语句 

<!DOCTYPE HTML>
<html lang="en-US">
<head>
    <meta charset="UTF-8">
    <title>2.13.JavaScript.条件语句</title>
</head>
<body>
    <script type="text/javascript">
        
        /*
        //if else语句
        if( 100 > 10 ){
            document.write("真");
        }else{
            document.write("假");
        }
        */
        //
        
        function checkChange(){
            var username = document.getElementById("username");//获取到html节点
if( username.value == ""){
                alert("用户名不能为空");
            }else if( username.value == "admin" || username.value == "xiaozhanga4"){
                alert("恭喜你，" + username.value);
            }else{
                alert("用户名错误");
            }
            
        }
        
    </script>
    
    <form method="post" action="">
        <input type="text" name="username" id="username"/>
        <input type="submit" value="提交" onclick="checkChange();"/>
    </form>
    
    
</body>
</html>
posted @ 2012-03-15 17:34  校长阿四  阅读(187)  评论(0)  编辑  收藏  举报