How to Reliably Track Changes in Radio Button Groups Across Browsers?

Cross-Browser Solution for Change Event in Radio Button Groups

In radio button groups where multiple inputs share the same name, the onChange event can be unreliable for tracking changes. This is because onChange doesn't fire when a radio button is deselected.

Workaround: Event Delegation and State Management

One workaround is to use event delegation and state management to track the previously checked radio button. By adding a single event listener to the form containing the radio buttons, we can capture all change events and update our state accordingly:

<code class="javascript">var rad = document.myForm.myRadios;
var prev = null;

for (var i = 0; i < rad.length; i++) {
    rad[i].addEventListener('change', function() {
        (prev) ? console.log(prev.value): null;
        if (this !== prev) {
            prev = this;
        }
        console.log(this.value)
    });
}</code>

This script assigns each radio button a change event listener. When a change occurs, it logs the value of the previously checked radio button (if any) before updating the 'prev' variable to refer to the current checked radio button.

Alternate Approaches

• Event bubbling can be used instead of direct event delegation. In this approach, the event listener is added to the form element, and the event bubbles up to the form when a radio button is clicked. However, this approach may have performance implications.
• Click events can be used as a fallback for onChange. While click events are triggered regardless of whether a radio button is checked or unchecked, they lack the context of the radio button group's state.

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