js中判断用户输入的值是否为空的简单实例

前端技术 2023/09/08 JavaScript

在js中判断用户输入的值是否为空,这是大家用得非常多的. 这没有什么好写的. 而我却写了. 原因只是自以为是的认为我的这些代码写得不错, 供大家参考一下.

这是摘自的我一个项目的中的用户注册页面.对于大多数人来说,这都几乎是100%经历过的.
贴代码吧,这些代码都是用js写的. 不难,很容易看懂. 看的时候,只要区别两个js类就行了.
前台页面代码:reguser.aspx

复制代码 代码如下:

<%@ Page language=\"c#\" Codebehind=\"RegUser.aspx.cs\" AutoEventWireup=\"false\" Inherits=\"Enterprise.Web.RegUser\" %>
<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 Transitional//EN\" >
<html>
    <head>
        <title>用户注册</title>
        <meta name=\"GENERATOR\" Content=\"Microsoft Visual Studio .NET 7.1\">
        <meta name=\"CODE_LANGUAGE\" Content=\"C#\">
        <meta name=\"vs_defaultClientScript\" content=\"JavaScript\">
        <meta name=\"vs_targetSchema\" content=\"http://schemas.microsoft.com/intellisense/ie5\">
        <LINK rel=\"stylesheet\" type=\"text/css\" href=\"/CSS/EnterpriseWebSite.css\">
        <script src=\"/js/CommonFunction.js\" ></script>
        <script>
            var reg    = {};
            reg.userName    = \'\';
            reg.password    = \'\';
            reg.confirmPassword    = \'\';
            reg.question    = \'\';
            reg.answer    = \'\';
            reg.url    = \'\';
            reg.sex    = 1;
            reg.email    = \'\';
            reg.tel    = \'\';
            reg.mobile    = \'\';
            reg.qq    = \'\';
            reg.address    = \'\';
            reg.postalcode    = \'\';
            reg.form    = null;

            function btnSubmit_onclick()
            {
                reg.form    = document.forms[0];
                var comFun    = new commonFunction();

                if(!comFun.checkIsEmpty(reg.form))
                {
                    return false;
                }

                if(comFun.$getElementById(\'txtPassword\').value!=comFun.$getElementById(\'txtConfirmPassword\').value)
                {
                    alert(\'两次密码输入不一致\');
                    comFun.$getElementById(\'txtConfirmPassword\').select();
                    return false;
                }

                reg.userName    = comFun.$getElementById(\'txtUserName\');
                reg.password    = comFun.$getElementById(\'txtPassword\');
                reg.question    = comFun.$getElementById(\'txtQuestion\');
                reg.answer        = comFun.$getElementById(\'txtAnswer\');
                reg.url            = comFun.$getElementById(\'txtUrl\');
                reg.email        = comFun.$getElementById(\'txtEmail\');
                reg.tel            = comFun.$getElementById(\'txtTel\');
                reg.mobile        = comFun.$getElementById(\'txtMobile\');
                reg.qq            = comFun.$getElementById(\'txtQQ\');
                reg.address        = comFun.$getElementById(\'txtAddress\');
                reg.postalcode    = comFun.$getElementById(\'txtPostalcode\');

                var es    = comFun.$getElementsByName(\'sex\');
                var eL    = es.length;
                for(var i=0; i<eL; i++)
                {
                    var    e    = es[i];
                    if(e.checked)
                    {
                        reg.sex    = e.value;
                        break;
                    }
                }

                RegUser.Reg(reg.userName.value, reg.password.value, reg.question.value, reg.answer.value, reg.url.value, reg.sex.value, reg.email.value, reg.tel.value, reg.mobile.value, reg.qq.value, reg.address.value, reg.postalcode.value, callback_Reg);
            }

            function callback_Reg(res)
            {
                var rv    = res.value;
                if(rv)
                {
                    alert(\'注册成功!\');
                    window.location.href=\'/Default.aspx\';
                }
                else
                {
                    alert(\'有错误发生,注册失败!有可能是用户名或者域名被别人注册过了!\');
                }
            }

            // 检测用户名的域名是否被其它用户注册过了
            function checkIsRegistered(obj, errorS, t)
            {
                var v    = obj.value;

                var rv    = RegUser.CheckIsRegistered(v, t).value;
                if(rv)
                {
                    alert(errorS);
                    obj.select();
                    return false;
                }
            }
        </script>
    </head>
    <body MS_POSITIONING=\"GridLayout\">
        <form id=\"Form1\" method=\"post\" runat=\"server\">
            <table width=\"98%\" border=\"0\" align=\"center\" cellpadding=\"3\" cellspacing=\"0\">
                <tr>
                    <td width=\"16%\"><div align=\"right\">用户名:</div>
                    </td>
                    <td width=\"84%\"><input type=\"text\" id=\"txtUserName\" onblur=\"checkIsRegistered(this, \'该用户名已经被注册,请使用其它的!\', 1)\" maxlength=\"15\" isRequired=\"true\" isValidate=\"true\" errorSForEmpty=\"用户名不能为空!\" errorSForValidate=\"匹配出错!以字母开头,允许3-16字节,允许字母数字下划线以及许可的安全符号!\" validatePattern=\"/^[a-zA-Z][a-zA-Z0-9_$%]{2,15}$/\" title=\"用户名必须填写!\"><font color=\"#ff0000\">*</font></td>
                </tr>
                <tr>
                    <td><div align=\"right\">密码:</div>
                    </td>
                    <td><input type=\"password\" id=\"txtPassword\" maxlength=\"15\" isRequired=\"true\" isValidate=\"true\" errorSForEmpty=\"密码不能为空!\" errorSForValidate=\"匹配出错!要求3-16字节,允许字母数字下划线以及许可的安全符号!!\" validatePattern=\"/^[a-zA-Z0-9_$%]{2,15}$/\" title=\"密码必须填写!\"><font color=\"#ff0000\">*</font></td>
                </tr>
                <tr>
                    <td><div align=\"right\">确认密码:</div>
                    </td>
                    <td><input type=\"password\" id=\"txtConfirmPassword\" isRequired=\"true\" errorSForEmpty=\"确认密码不能为空!\"><font color=\"#ff0000\">*</font></td>
                </tr>
                <tr>
                    <td><div align=\"right\">密码提示问题:</div>
                    </td>
                    <td><input type=\"text\" id=\"txtQuestion\" maxlength=\"50\" isRequired=\"true\" isValidate=\"true\" errorSForEmpty=\"密码提示问题没有填写!\" errorSForValidate=\"长度必须在8-50个字之间且不得有空格!\" validatePattern=\"/\\S{8,50}/\" title=\"密码提示问题必须填写!\"><font color=\"#ff0000\">*</font></td>
                </tr>
                <tr>
                    <td><div align=\"right\">密码问题答案:</div>
                    </td>
                    <td><input type=\"text\" id=\"txtAnswer\" maxlength=\"50\" isRequired=\"true\" isValidate=\"true\" errorSForEmpty=\"密码问题答案没有填写!\" errorSForValidate=\"长度必须在8-50个字之间且不得有空格!\" validatePattern=\"/\\S{8,50}/\" title=\"密码问题答案必须填写!\"><font color=\"#ff0000\">*</font></td>
                </tr>
                <tr>
                    <td><div align=\"right\">站点Url:</div>
                    </td>
                    <td><input type=\"text\" id=\"txtUrl\" onblur=\"checkIsRegistered(this, \'该Url已经被注册,请使用其它的!\', 2)\" maxlength=\"20\" isRequired=\"true\" isValidate=\"true\" errorSForEmpty=\"站点Url不能为空!\" errorSForValidate=\"站点Url格式不对!\" validatePattern=\"/^[a-zA-Z0-9]{1,20}$/\" title=\"站点Url必须填写!\"><font color=\"#ff0000\">*</font></td>
                </tr>
                <tr>
                    <td><div align=\"right\">性别:</div>
                    </td>
                    <td><input type=\"radio\" id=\"boy\" name=\"sex\" value=\"1\" checked>男  <input type=\"radio\" id=\"girl\" name=\"sex\" value=\"0\">女</td>
                </tr>
                <tr>
                    <td><div align=\"right\">Email:</div>
                    </td>
                    <td><input type=\"text\" id=\"txtEmail\" isValidate=\"true\" errorSForValidate=\"Email格式不正确!\" validatePattern=\"/^.+\\@(\\[?)[a-zA-Z0-9\\-\\.]+\\.([a-zA-Z]{2,3}|[0-9]{1,3})(\\]?)$/\"></td>
                </tr>
                <tr>
                    <td><div align=\"right\">固定电话:</div>
                    </td>
                    <td><input type=\"text\" id=\"txtTel\" isRequired=\"true\" isValidate=\"true\" errorSForEmpty=\"固定电话不能为空!\" errorSForValidate=\"固定电话格式不对!请使用0592-5555555的格式!\" validatePattern=\"/^(\\d{3}-|\\d{4}-)?(\\d{8}|\\d{7})$/\" title=\"固定电话必须填写!\"><font color=\"#ff0000\">*</font></td>
                </tr>
                <tr>
                    <td><div align=\"right\">移动电话:</div>
                    </td>
                    <td><input type=\"text\" id=\"txtMobile\" isValidate=\"true\" errorSForValidate=\"移动电话格式不正确!\" validatePattern=\"/^1\\d{10}$/\"></td>
                </tr>
                <tr>
                    <td><div align=\"right\">QQ:</div>
                    </td>
                    <td><input type=\"text\" id=\"txtQQ\" isValidate=\"true\" errorSForValidate=\"QQ格式不正确!\" validatePattern=\"/^[1-9]*[1-9][0-9]*$/\"></td>
                </tr>
                <tr>
                    <td><div align=\"right\">住址:</div>
                    </td>
                    <td><input type=\"text\" id=\"txtAddress\"></td>
                </tr>
                <tr>
                    <td><div align=\"right\">邮编:</div>
                    </td>
                    <td><input type=\"text\" id=\"txtPostalcode\" maxlength=\"6\" isValidate=\"true\" errorSForValidate=\"邮编不正确!\" validatePattern=\"/^\\d{6}/\"></td>
                </tr>
                <tr>
                    <td><div align=\"right\">操作:</div>
                    </td>
                    <td><input type=\"button\" value=\"注册\" id=\"btnSubmit\" onclick=\"btnSubmit_onclick()\">  <input type=\"reset\" value=\"重置\"></td>
                </tr>
            </table>
        </form>
    </body>
</html>

在上面的代码中,有包含了一个CommonFunction.js文件,下面这是他的内容:
复制代码 代码如下:

/***********************************************************
*
*    公共js函数
*
***********************************************************/
function commonFunction()
{
    // check value is null or empty
    this.checkIsEmpty    = function(obj)
    {
        var flag    = true;
        for(var i=0; i<obj.length; i++)
        {
            var e    = obj.item(i);
            if(e.isRequired)
            {   
                if(e.value==\'\')
                {
                    alert(e.errorSForEmpty);
                    e.focus();
                    flag    = false;
                    break;
                }
            }

            if(e.isValidate)
            {
                if(this.checkValidate(e)==false)
                {
                    alert(e.errorSForValidate);
                    e.select();
                    e.focus();
                    flag    = false;
                    break;
                }
            }
        }

        return flag;
    }

    // check value is validate
    this.checkValidate    = function(e)
    {
        var v    = e.value;
        if(v!=\'\')
        {
            return this.checkReg(e.validatePattern, v);
        }
    }

    // regexp validate
    this.checkReg    = function(pattern, value)
    {
        pattern    = pattern.substring(1, pattern.length-1);
        var reg    = new RegExp(pattern);
        if(!reg.test(value))
        {
            return false;
        }
    }

    // return an Element By id object for what id.
    this.$getElementById    = function(id)
    {
        var e    = document.getElementById(id);

        if(e!=\'undefined\')
        {
            return e;
        }

        return;
    }

    // return an Element By name object for what id.
    this.$getElementsByName    = function(id)
    {
        var e    = document.getElementsByName(id);

        if(e!=\'undefined\')
        {
            return e;
        }

        return;
    }
}

贴一张效果图片:

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