js中判断用户输入的值是否为空的简单实例_javascript技巧

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:

   
       
       
       
       
       
       
       
        <script><BR> var reg = {};<BR> reg.userName = '';<BR> reg.password = '';<BR> reg.confirmPassword = '';<BR> reg.question = '';<BR> reg.answer = '';<BR> reg.url = '';<BR> reg.sex = 1;<BR> reg.email = '';<BR> reg.tel = '';<BR> reg.mobile = '';<BR> reg.qq = '';<BR> reg.address = '';<BR> reg.postalcode = '';<BR> reg.form = null;<br><br> function btnSubmit_onclick()<BR> {<BR> reg.form = document.forms[0];<BR> var comFun = new commonFunction();<br><br> if(!comFun.checkIsEmpty(reg.form))<BR> {<BR> return false;<BR> }<br><br> if(comFun.$getElementById('txtPassword').value!=comFun.$getElementById('txtConfirmPassword').value)<BR> {<BR> alert('两次密码输入不一致');<BR> comFun.$getElementById('txtConfirmPassword').select();<BR> return false;<BR> }<br><br> reg.userName = comFun.$getElementById('txtUserName');<BR> reg.password = comFun.$getElementById('txtPassword');<BR> reg.question = comFun.$getElementById('txtQuestion');<BR> reg.answer = comFun.$getElementById('txtAnswer');<BR> reg.url = comFun.$getElementById('txtUrl');<BR> reg.email = comFun.$getElementById('txtEmail');<BR> reg.tel = comFun.$getElementById('txtTel');<BR> reg.mobile = comFun.$getElementById('txtMobile');<BR> reg.qq = comFun.$getElementById('txtQQ');<BR> reg.address = comFun.$getElementById('txtAddress');<BR> reg.postalcode = comFun.$getElementById('txtPostalcode');<br><br> var es = comFun.$getElementsByName('sex');<BR> var eL = es.length;<BR> for(var i=0; i<eL; i++)<BR> {<BR> var e = es[i];<BR> if(e.checked)<BR> {<BR> reg.sex = e.value;<BR> break;<BR> }<BR> }<br><br> 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);<BR> }<br><br> function callback_Reg(res)<BR> {<BR> var rv = res.value;<BR> if(rv)<BR> {<BR> alert('注册成功!');<BR> window.location.href='/Default.aspx';<BR> }<BR> else<BR> {<BR> 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！');<BR> }<BR> }<br><br> // 检测用户名的域名是否被其它用户注册过了<BR> function checkIsRegistered(obj, errorS, t)<BR> {<BR> var v = obj.value;<br><br> var rv = RegUser.CheckIsRegistered(v, t).value;<BR> if(rv)<BR> {<BR> alert(errorS);<BR> obj.select();<BR> return false;<BR> }<BR> }<BR> </script>
   
   
       

           
               
                   
                   
               
               
                   
                   
               
               
                   
                   
               
               
                   
                   
               
               
                   
                   
               
               
                   
                   
               
               
                   
                   
               
               
                   
                   
               
               
                   
                   
               
               
                   
                   
               
               
                   
                   
               
               
                   
                   
               
               
                   
                   
               
               
                   
                   
               
           

用户名:	*
密码:	*
确认密码:	*
密码提示问题:	*
密码问题答案:	*
站点Url:	*
性别:	男  女
Email:
固定电话:	*
移动电话:
QQ:
住址:
邮编:
操作:

       

   

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        {
            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: