求助HTML高手radio如何响应失去选中事件_html/css_WEB-ITnose
呵呵~！
我做的东西比较恶心
现在遇到了个问题就是input的radio控件响应事件问题
是这样：一个radio不光要响应被选中的事件，还要监听自己被撤销选中的事件
比如我有个选择题，A，B，C三个选项
用户在页面先选了A，根据某些业务逻辑，选了A以后是要进行一些相关操作的
但是这时候用户想了一下，觉得选A不好，改选B了
那么刚才根据用户选了A这一结果执行的操作，就要实现逆操作
我想设置radio的 onpropertychange事件来实现这个操作，但是发现把JavaScript方法注册到事件上以后
用户点中radio的时候，浏览器调用了2次该方法
而且似乎是在radio的checked属性被设置为true之前调用一次，设置为true之后调用一次
而当选了同组其他radio的时候，这个方法只执行了一次
很郁闷
所以来问问
有没有方法监听radio控件被选中和被撤销的事件啊？
谢谢大家了
回复讨论(解决方案)
换个思路。如果改选B，那么会触发事件。这样同样可以监听A撤消啊
试试 onclick
用一个全局变量记住当前选项
<html> <script language="javascript" defer="defer"> var cur;function check(){ var val; var rds = document.forms[0].rd; for(var i=0;i<rds.length;i++){ if(rds[i].checked){ val = i; break; } } if(val != cur){cur = val; alert("changed")}} window.onload=function(){ var rds = document.forms[0].rd; for(var i=0;i<rds.length;i++){ if(rds[i].checked){ cur = i; break; } }}</script> <body><form><input type="radio" name="rd" value="0" checked="checked" onclick="check()"> 0<br><input type="radio" name="rd" value="1" onclick="check()"> 1<br><input type="radio" name="rd" value="2" onclick="check()"> 2<br></form></body> </html>
<div id=radios> a <input type=radio name=a value=a > b <input type=radio name=a value=b> c <input type=radio name=a value=c></div><script language="javascript"><!--var obj=document.getElementById("radios").getElementsByTagName("input")for (var i=0;i<obj.length;i++){(function(k){obj[i].onclick=function(){cha(k)}})(i)}var lastChecked=nullfunction cha(k){if (lastChecked==k)returnif (lastChecked!=null){ //处理obj[lastChecked] alert("上次选中："+lastChecked)}lastChecked=k//处理obj[lastChecked]alert("本次选中："+lastChecked)}//--></script> 使用临时变量是不行的
因为页面上的选择题的数量，以及选择题和填空题
以及题目之间的跳转关系
比如：单选某一选项要跳转到哪个题
选择题之间选项的组合，选择题与填空题之间的组合
等等都是用户在设计试卷的时候指定的
不是写死在页面上的
变量可以动态创建，或用数组，不需要写死。
路过 学习
用一个全局变量记住当前选项
HTML code
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
AI Hentai Generator
Generate AI Hentai for free.
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
Difficulty in updating caching of official account web pages: How to avoid the old cache affecting the user experience after version update?
Mar 04, 2025 pm 12:32 PM
The official account web page update cache, this thing is simple and simple, and it is complicated enough to drink a pot of it. You worked hard to update the official account article, but the user still opened the old version. Who can bear the taste? In this article, let’s take a look at the twists and turns behind this and how to solve this problem gracefully. After reading it, you can easily deal with various caching problems, allowing your users to always experience the freshest content. Let’s talk about the basics first. To put it bluntly, in order to improve access speed, the browser or server stores some static resources (such as pictures, CSS, JS) or page content. Next time you access it, you can directly retrieve it from the cache without having to download it again, and it is naturally fast. But this thing is also a double-edged sword. The new version is online,
How to efficiently add stroke effects to PNG images on web pages?
Mar 04, 2025 pm 02:39 PM
This article demonstrates efficient PNG border addition to webpages using CSS. It argues that CSS offers superior performance compared to JavaScript or libraries, detailing how to adjust border width, style, and color for subtle or prominent effect
How do I use HTML5 form validation attributes to validate user input?
Mar 17, 2025 pm 12:27 PM
The article discusses using HTML5 form validation attributes like required, pattern, min, max, and length limits to validate user input directly in the browser.
What is the purpose of the <datalist> element?
Mar 21, 2025 pm 12:33 PM
The article discusses the HTML <datalist> element, which enhances forms by providing autocomplete suggestions, improving user experience and reducing errors.Character count: 159
What is the purpose of the <progress> element?
Mar 21, 2025 pm 12:34 PM
The article discusses the HTML <progress> element, its purpose, styling, and differences from the <meter> element. The main focus is on using <progress> for task completion and <meter> for stati
What is the purpose of the <meter> element?
Mar 21, 2025 pm 12:35 PM
The article discusses the HTML <meter> element, used for displaying scalar or fractional values within a range, and its common applications in web development. It differentiates <meter> from <progress> and ex
What are the best practices for cross-browser compatibility in HTML5?
Mar 17, 2025 pm 12:20 PM
Article discusses best practices for ensuring HTML5 cross-browser compatibility, focusing on feature detection, progressive enhancement, and testing methods.
What is the purpose of the <iframe> tag? What are the security considerations when using it?
Mar 20, 2025 pm 06:05 PM
The article discusses the <iframe> tag's purpose in embedding external content into webpages, its common uses, security risks, and alternatives like object tags and APIs.
