js中判断用户输入的值是否为空的简单实例

作者：Eve Cole 更新时间：2025-03-23 05:16:01

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>

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>

<tr>

</td>

</tr>

<tr>

</td>

</tr>

<tr>

</td>

</tr>

<tr>

<td><div align="right">密码提示问题:</div>

</td>

</tr>

<tr>

<td><div align="right">密码问题答案:</div>

</td>

</tr>

<tr>

<td><div align="right">站点Url:</div>

</td>

</tr>

<tr>

</td>

</tr>

<tr>

<td><div align="right">Email:</div>

</td>

</tr>

<tr>

</td>

</tr>

<tr>

</td>

</tr>

<tr>

</td>

</tr>

<tr>

</td>

</tr>

<tr>

</td>

</tr>

<tr>

</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: