Кнопка
Рассмотрим пример, как нужно обрабатывать нажатия кнопки в форме с помощью JavaScript.
Создадим простейшую форму.
На данный момент кнопка ничего не делает. Получим доступ к кнопке.
var button = getElementById("addButton"); Далее следует создать код, который будет выполняться при нажатии кнопки.
function handleButtonClick
Осталось подключить созданную функцию к переменной
button.onclick = handleButtonClick; window.onload = init; function init() < var button = document.getElementById("addButton") button.onclick = handleButtonClick; >function handleButtonClick() При нажатии на кнопку появляется сообщение.
Идём дальше. Мы хотим получить текст, введённый пользователем в текстовом поле. Когда пользователь вводит текст, то у элемента input type=»text» в свойстве value появляется значение, которое и содержит текст пользователя. Таким образом, нам нужно сначала получить доступ к элементу страницы по идентификатору, а затем его свойство.
var button2 = document.getElementById("addButton2") button2.onclick = handleButtonClick2; function handleButtonClick2() Теперь выводится сообщение, в котором содержится имя кота. Не помешает небольшая проверка, что текст был введён.
function handleButtonClick2() < var textInput = document.getElementById("catNameInput2"); var catName = textInput.value; if(catName == "")< alert("Введите имя кота, пожалуйста"); >else < alert("Добавлено новое имя кота! " + catName); >> Третий шаг — выводить имена котов на самой странице. Мы уже приготовили список ul, к которому тоже можно получить доступ и добавлять дочерние элементы. Для получения доступа используем знакомый метод getElementById(). Для динамического создания нового элемента используется метод document.createElement(). После создания мы можем настроить элемент, например, прописав текст. Для текста элемента списка будем использовать переменную, которая содержит имя кота. Создав новый элемент, его необходимо добавить к родительскому элементу через appendChild().
function handleButtonClick3() < var textInput = document.getElementById("catNameInput3"); var catName = textInput.value; if(catName == "")< alert("Введите имя кота, пожалуйста"); >else < var ul = document.getElementById("catlist3"); var li = document.createElement("li"); li.innerHTML = catName; ul.appendChild(li); alert("Добавлено новое имя кота! " + catName); >> Новые способы
В последнее время стали использовать другой код. Например, используют const вместо var, вместо onclick — addEventListener.
Также вместо getElementById() можно использовать querySelector(). А в addEventListener использовать другой формат вызова функции.
.button < background-color: #33ae74; transition: background-color 0.5s ease-out; >.button.is-active Атрибут onclick
Также можно использовать готовый атрибут у кнопки onclick.
Element: click event
An element receives a click event when a pointing device button (such as a mouse’s primary mouse button) is both pressed and released while the pointer is located inside the element.
If the button is pressed on one element and the pointer is moved outside the element before the button is released, the event is fired on the most specific ancestor element that contained both elements.
click fires after both the mousedown and mouseup events have fired, in that order.
Syntax
Use the event name in methods like addEventListener() , or set an event handler property.
addEventListener("click", (event) => >); onclick = (event) => >;
Event type
Event properties
This interface also inherits properties of its parents, UIEvent and Event . MouseEvent.altKey Read only Returns true if the alt key was down when the mouse event was fired. MouseEvent.button Read only The button number that was pressed (if applicable) when the mouse event was fired. MouseEvent.buttons Read only The buttons being pressed (if any) when the mouse event was fired. MouseEvent.clientX Read only The X coordinate of the mouse pointer in local (DOM content) coordinates. MouseEvent.clientY Read only The Y coordinate of the mouse pointer in local (DOM content) coordinates. MouseEvent.ctrlKey Read only Returns true if the control key was down when the mouse event was fired. MouseEvent.layerX Non-standard Read only Returns the horizontal coordinate of the event relative to the current layer. MouseEvent.layerY Non-standard Read only Returns the vertical coordinate of the event relative to the current layer. MouseEvent.metaKey Read only Returns true if the meta key was down when the mouse event was fired. MouseEvent.movementX Read only The X coordinate of the mouse pointer relative to the position of the last mousemove event. MouseEvent.movementY Read only The Y coordinate of the mouse pointer relative to the position of the last mousemove event. MouseEvent.offsetX Read only The X coordinate of the mouse pointer relative to the position of the padding edge of the target node. MouseEvent.offsetY Read only The Y coordinate of the mouse pointer relative to the position of the padding edge of the target node. MouseEvent.pageX Read only The X coordinate of the mouse pointer relative to the whole document. MouseEvent.pageY Read only The Y coordinate of the mouse pointer relative to the whole document. MouseEvent.relatedTarget Read only The secondary target for the event, if there is one. MouseEvent.screenX Read only The X coordinate of the mouse pointer in global (screen) coordinates. MouseEvent.screenY Read only The Y coordinate of the mouse pointer in global (screen) coordinates. MouseEvent.shiftKey Read only Returns true if the shift key was down when the mouse event was fired. MouseEvent.mozInputSource Non-standard Read only The type of device that generated the event (one of the MOZ_SOURCE_* constants). This lets you, for example, determine whether a mouse event was generated by an actual mouse or by a touch event (which might affect the degree of accuracy with which you interpret the coordinates associated with the event). MouseEvent.webkitForce Non-standard Read only The amount of pressure applied when clicking. MouseEvent.x Read only Alias for MouseEvent.clientX . MouseEvent.y Read only Alias for MouseEvent.clientY .
Usage notes
The MouseEvent object passed into the event handler for click has its detail property set to the number of times the target was clicked. In other words, detail will be 2 for a double-click, 3 for triple-click, and so forth. This counter resets after a short interval without any clicks occurring; the specifics of how long that interval is may vary from browser to browser and across platforms. The interval is also likely to be affected by user preferences; for example, accessibility options may extend this interval to make it easier to perform multiple clicks with adaptive interfaces.
Examples
HTML
JavaScript
const button = document.querySelector("button"); button.addEventListener("click", (event) => button.textContent = `Click count: $event.detail>`; >);
Result
Try making rapid, repeated clicks on the button to increase the click count. If you take a break between clicks, the count will reset.
Specifications
Browser compatibility
See also
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This page was last modified on Jun 26, 2023 by MDN contributors.
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