本周笔记

<fieldset>
    <legend>验证IP地址</legend>
    <input type="text" id="domain" value="" style="width:150px;height:22px;" class="">
    <button value="查询" onclick="domain_check()">查询</button>    
    <script>
    function domain_check(){        
        var domain = $("#domain").val();    
        var reg =  /^(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])$/
            if (!reg.test(domain)) {
                if((domain != "")&&(domain != null)){
                alert("请输入正确的用户IP地址");
                return false;
                }
            }
    }
</script>
</fieldset>