OnInput

OnInput refers to the HTML oninput attribute and the input event in web development. The input event fires when the value of an input, textarea, or other editable element changes as a result of user input. It also applies to contenteditable elements in many cases. The oninput attribute is a way to attach a handler directly in the markup.

In contrast to the change event, which typically fires when a control loses focus after its value has changed, oninput fires immediately as the user types or otherwise modifies the value. This makes oninput well suited for real-time feedback or validation.

Common uses include live form validation, character counters, and live search suggestions. The event object is an InputEvent; for text-like controls, e.target.value gives the current value. Depending on the browser, e.data may contain the most recently inserted characters, and e.inputType indicates how the input changed (for example, insertText or deleteContentBackward).

Examples:

HTML: <input id="field" oninput="handleInput(this.value)">

JavaScript: document.getElementById('field').addEventListener('input', function(e) { console.log(e.target.value); });

Compatibility: oninput is supported by all modern browsers and many legacy browsers. If you need to support very old environments, consider providing a fallback to the change event or using feature detection and polyfills as appropriate.