Input tags with the type attribute checkbox can be grouped like radio buttons so that several checkboxes have the same name. However, any number of checkboxes can be selected by the user. Working with checkboxes in JavaScript is similar to but not exactly the same as working with radio buttons. Here is a short example that demonstrates getting values from checkboxes and radio buttons in the same form:

Music Survey

I enjoy: Classical Chamber Jazz Rock Punk
Favourite Performer:
 Aitken Coltrane Julliard Kronos Waits

Getting all the values

A series of checkboxes with the same name are reflected as an array of checkbox objects. In this example each check box input tag is named Music but has a different value. Since there are identically named input tags of the same type, an array of checkbox objects named Music is created. When the button in this form is pressed, it passes a reference to the form to a function named, in this case, showBoxes(frm). The function loops through the checkbox array within the form. To access the check box array from the form reference it is only necessary to append the name of the checkboxes to the form reference:

frm.Music

For example to access the number of elements in the array:

frm.Music.length

or if the variable i contains the index of one of the elements, here is how you would check to see if that element had been checked:

if (frm.Music[i].checked)

or get that element's value:

frm.Music[i].value

Since many values may be checked, this example gathers the values from each by appending each value on to the end of a string. Since the string is eventually displayed in an alert dialog each value is separated by a "\n", or new line character. In this case the string is named message

message = message + frm.Music[i].value + "\n"

Here is the complete page:

<HTML>

<HEAD>

<TITLE>JavaScript - Reading Checkboxes and Radio Buttons</TITLE>

<SCRIPT LANGUAGE="JavaScript">

<!--

function showBoxes(frm){

   var message = "Your chose:\n\n"

   //For each checkbox see if it has been checked, record the value.

   for (i = 0; i < frm.Music.length; i++)

      if (frm.Music[i].checked){

         message = message + frm.Music[i].value + "\n"

      }

   //For each radio button if it is checked get the value and break.

   for (var i = 0; i < frm.Performer.length; i++){

      if (frm.Performer[i].checked){

         message = message + "\n" + frm.Performer[i].value

         break

      }

   }

   alert(message)

}

//NOTE THE onClick="" empty event handlers in the checkbox and radio input fields below

//are there to fix a bug in Netscape 2.0X. Placing an onClick handler in imput fields fixes

//a bug where input objects inside tables are reflected more than once.

//-->

</SCRIPT>

</HEAD>

<BODY BGCOLOR="#ffffff">

<FORM NAME="boxes">

<HR size=1 noshade>

<h2>Music Survey </h2>

<TABLE BORDER="1" CellSpacing="0" CellPadding="6">

<TR>

  <TD align="right">I enjoy:</TD>

  <TD><INPUT TYPE="Checkbox" NAME="Music"  VALUE="Classical" onClick="" CHECKED>Classical</TD>

  <TD><INPUT TYPE="Checkbox" NAME="Music"  VALUE="Chamber"   onClick="">Chamber</TD>

  <TD><INPUT TYPE="Checkbox" NAME="Music"  VALUE="Jazz"      onClick="" CHECKED>Jazz</TD>

  <TD><INPUT TYPE="Checkbox" NAME="Music"  VALUE="Rock"      onClick="">Rock</TD>

  <TD><INPUT TYPE="Checkbox" NAME="Music"  VALUE="Punk"      onClick="">Punk</TD>

</TR>

<TR>

  <TD><div align="right">Favourite Performer:</div></TD>

  <TD><INPUT TYPE="radio" NAME="Performer" VALUE="Aitken"    onClick="">Aitken</TD>

  <TD><INPUT TYPE="radio" NAME="Performer" VALUE="Coltrane"  onClick="" CHECKED>Coltrane</TD>

  <TD><INPUT TYPE="radio" NAME="Performer" VALUE="Julliard"  onClick="">Julliard</TD>

  <TD><INPUT TYPE="radio" NAME="Performer" VALUE="Kronos"    onClick="">Kronos</TD>

  <TD><INPUT TYPE="radio" NAME="Performer" VALUE="Waits"     onClick="">Waits</TD>

</TR>

</TABLE>

<P>

<INPUT TYPE="Button" VALUE="Tell Us What You Like!" onClick="showBoxes(this.form)">

</P>

</FORM>

</BODY>

</HTML>

Reading CheckBoxes and Radio Buttons的更多相关文章

  1. playwright-python 处理Text input、Checkboxs 和 radio buttons（三）

    Text input 输入框输入元素,直接用fill方法即可,支持 <input>,<textarea>, [contenteditable] 和<label>这些 ...

  2. [Angular2 Form] Create Radio Buttons for Angular 2 Forms

    Using Radio Buttons in Angular 2 requires a basic understanding of forms as well as how their labels ...

  3. JSF 2 radio buttons example

    In JSF, "h:selectOneRadio" tag is used to render a set of HTML input element of type " ...

  4. mfc Radio Buttons

    添加单选按钮 关联变量 调试宏TRACE BOOL类型 一.添加一组单选按钮 二.添加第二组单选按钮 三.关联变量 四.单选按钮运用 void CMY_Dialog::OnBnClickedButto ...

  5. （转）Bootstrap 之 Metronic 模板的学习之路 - （4）源码分析之脚本部分

    https://segmentfault.com/a/1190000006709967 上篇我们将 body 标签主体部分进行了简单总览,下面看看最后的脚本部门. 页面结尾部分(Javascripts ...

  6. selenium docs

    Note to the Reader - Docs Being Revised for Selenium 2.0! Introduction Test Automation for Web Appli ...

  7. ASP.NET MVC异步上传文件

    自己做的一个小dome.贴出来分享一下: 前端: <form id="formfile" method="post" enctype="mult ...

  8. Asp.net DropDownList 自定义样式(想怎么改就怎么改！)

    最近在做一个asp.net的项目,需要对默认的dropdownlist样式进行美化,固有的dropdownlist的小箭头实在让人无法接受,于是开始在百度,google 上下求索,天不负有心人,终于找 ...

  9. Ajax.BeginForm 上传文件

    在 Mvc 中上传文件时通常使用 Html.BeginForm 标签,同时对Form 添加属性 enctype = "multipart/form-data",前端代码如下: @H ...

随机推荐

  1. Iocomp控件教程之Analog Display—模拟显示控件（优于EDIT控件）

    Analog Display是简洁的显示控件.用于显示指定准确度和单位的模拟值(实数),能够将准确度设置为0.使显示结果为整数. 第一步:建立MFC对话框 第二步:插入AnalogDisplay控件 ...

  2. 看看Spring的源码(二)——bean实例化

    首先来看一段代码,看过上一节的朋友肯定对这段代码并不陌生.这一段代码诠释了Spring加载bean的完整过程,包括读取配置文件,扫描包,加载类,实例化bean,注入bean属性依赖. public v ...

  3. 第十章 dubbo线程模型

    一 netty的线程模型 在netty中存在两种线程:boss线程和worker线程. 1 boss线程 作用: accept客户端的连接: 将接收到的连接注册到一个worker线程上 个数: 通常情 ...

  4. linux C++ 多线程使用pthread_cond 条件变量

    1. 背景 多线程中经常需要使用到锁(pthread_mutex_t)来完成多个线程之间的互斥操作. 但是互斥锁有一个明显到缺点: 只有两种状态,锁定和非锁定. 而条件变量则通过允许线程阻塞并等待另一 ...

  5. 解决Keyboard遮盖输入的几种办法

    一般来说,键盘遮挡主要有这么几种情况,一个是遮住UITextView,还有就是遮住UITextField,一般来说,比较推荐在UIScrollView或者UITableView里加入textfield ...

  6. JS滚轮事件onmousewheel

    典型的应用时鼠标滚轮滚动控制图片或者文字的大小,例如此类的转动鼠标滚轮实现缩放等等交互效果中,会用到 Mousewheel 事件.在大多数浏览器(IE6, IE7, IE8, Opera 10+, S ...

  7. Spring（二十一）：Spring JdbcTemplate、NamedParameterJdbcTemplate具名参数

    JdbcTemplate主要提供以下五类方法: execute方法:可以用于执行任何SQL语句,一般用于执行DDL语句: update方法及batchUpdate方法:update方法用于执行新增.修 ...

  8. Eclipse 2017最佳20个插件

    https://www.infoworld.com/article/2606814/development-tools/development-tools-12-eclipse-plug-ins-ev ...

  9. 教育单元测试mock框架优化之路（上）

    转载:https://sq.163yun.com/blog/article/169561874192850944 众所周知,mock对于单元测试,尤其是基于spring容器的单元测试,是非常重要的.它 ...

  10. CentOS7安装Docker与使用篇

    一.在CentOS7上安装Docker篇 1. 查看系统版本: $ cat /etc/redhat-release CentOS Linux release 7.0.1406 (Core) 2. 安装 ...