除了存储之前的状态，我不认为还有其他方法。 下面是使用jQuery的解决方案

<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script> 
<script type="text/javascript">
    var lastSelected;
    $(function () {
        //if you have any radio selected by default
        lastSelected = $('[name="myRadios"]:checked').val();
    });
    $(document).on('click', '[name="myRadios"]', function () {
        if (lastSelected != $(this).val() && typeof lastSelected != "undefined") {
            alert("radio box with value " + $('[name="myRadios"][value="' + lastSelected + '"]').val() + " was deselected");
        }
        lastSelected = $(this).val();
    });
</script>

<input type="radio" name="myRadios" value="1" />
<input type="radio" name="myRadios" value="2" />
<input type="radio" name="myRadios" value="3" />
<input type="radio" name="myRadios" value="4" />
<input type="radio" name="myRadios" value="5" />

在考虑了一会儿之后，我决定去掉变量并添加/删除类。这是我得到的:http://jsfiddle.net/BeQh3/2/

Yes there is no change event for currently selected radio button. But problem is when each radio button is taken as a separate element. Instead a radio group should be considered a single element like select. So change event is triggered for that group. If it is a select element we never worry about each option in it, but take only the selected option. We store the current value in a variable which will become the previous value, when a new option is selected. Similarly you have to use a separate variable for storing value of checked radio button.

如果您想要识别前一个单选按钮，则必须循环鼠标按下事件。

var radios = document.getElementsByName("myRadios");
var val;
for(var i = 0; i < radios.length; i++){
    if(radios[i].checked){
        val = radios[i].value;
    }
}

请看这个:http://jsfiddle.net/diode/tywx6/2/

这对我很有用

<input ID="TIPO_INST-0" Name="TIPO_INST" Type="Radio" value="UNAM" onchange="convenio_unam();">UNAM

<script type="text/javascript">
            function convenio_unam(){
                if(this.document.getElementById('TIPO_INST-0').checked){
                    $("#convenio_unam").hide();
                }else{
                    $("#convenio_unam").show(); 
                }                               
            }
</script>

这是最简单和最有效的函数，只需添加尽可能多的按钮到checked = false，并使每个单选按钮的onclick事件调用此函数。为每个收音机指定一个唯一的号码 按钮

function AdjustRadios(which) 
{
    if(which==1)
         document.getElementById("rdpPrivate").checked=false;
    else if(which==2)
         document.getElementById("rdbPublic").checked=false;
}

博士Tl;

'focusout'在'change'事件之前被分派-示例:

const radioName = 'radio';

// Add radios
document.body.innerHTML = `
<style>
input + label {
  margin-left: 1rem;
}
</style>
<form action="#" name="example-form">
  <fieldset>
    ${Array(5).fill(null, 0, 5).map((_, i) => {
        const offsetId = i + 1;
        const id = `radio-${offsetId}`;
        return `<label for="${id}">Radio ${offsetId}</label>
        <input type="radio" name="${radioName}" id="${id}" value="${offsetId}" />`;
      }).join('\n')}
  </fieldset>
</form>
`;

const {log} = console,

    form = document.forms['example-form']; 

form.addEventListener('submit', e => e.preventDefault());

form.addEventListener('change', e => {
    const {target} = e;
    if (target.matches(`[type="radio"][name="${radioName}"]`)) {
        log(`[${e.type}]: "${target.id}" selected;  Value: ${target.value}`);
    }
});

form.addEventListener('focusout', e => {
    const {target} = e,

        soonToBePrevValue = target && target.form ? 
            target.form.elements[radioName].value : null;
    
    if (!target.matches(`[type="radio"][name="${radioName}"]`) || !soonToBePrevValue) {
        return;
    }

    // value, for '[name="radio"]', contained in form, will change after 'focusout' event
    // has completed it's bubbling stage.
    log(`[${e.type}]: previously selected radio value: ` + 
        `${soonToBePrevValue}`);
        
    // log("Soon to be \"previous\" radio: ", target);
});

斯菲德尔

我想做两点改变:

<input type="radio" name="myRadios" onclick="handleClick(this);" value="1" />
<input type="radio" name="myRadios" onclick="handleClick(this);" value="2" />

使用onclick处理程序而不是onchange -您正在更改无线电输入的“已检查状态”，而不是值，因此不会发生更改事件。 使用单个函数，并将其作为参数传递，这将便于检查当前选择的值。

ETA:除了handleClick()函数，您还可以在页面作用域变量中跟踪收音机的原始/旧值。那就是:

var currentValue = 0;
function handleClick(myRadio) {
    alert('Old value: ' + currentValue);
    alert('New value: ' + myRadio.value);
    currentValue = myRadio.value;
}

var currentValue = 0; 函数handleClick(myRadio) { alert('旧值:' + currentValue); alert('新值:' + myRadio.value); currentValue = myRadio.value; ｝ <input type="radio" name=" my" onclick="handleClick(this);" value="1" /> . <input type="radio" name=" my" onclick="handleClick(this);" value="2" /> .