<input>
elements of type
button
are rendered as simple push buttons, which can be programmed to control custom functionality anywhere on a webpage as required when assigned an event handler function (typically for the
click
event).
注意
: While
<input>
elements of type
button
are still perfectly valid HTML, the newer
<button>
element is now the favored way to create buttons. Given that a
<button>
’s label text is inserted between the opening and closing tags, you can include HTML in the label, even images.
| 值 |
A
DOMString
used as the button's label
|
| 事件 |
click
|
| Supported common attributes |
type
and
value
|
| IDL attributes |
value
|
| 方法 | None |
An
<input type="button">
elements'
value
attribute contains a
DOMString
that is used as the button's label.
<input type="button" value="Click Me">
If you don't specify a
value
, you get an empty button:
<input type="button">
<input type="button">
elements have no default behavior (their cousins,
<input type="submit">
and
<input type="reset">
are used to submit and reset forms, respectively). To make buttons do anything, you have to write JavaScript code to do the work.
We'll begin by creating a simple button with a
click
event handler that starts our machine (well, it toggles the
value
of the button and the text content of the following paragraph):
<form> <input type="button" value="Start machine"> </form> <p>The machine is stopped.</p>
const button = document.querySelector('input');
const paragraph = document.querySelector('p');
button.addEventListener('click', updateButton);
function updateButton() {
if (button.value === 'Start machine') {
button.value = 'Stop machine';
paragraph.textContent = 'The machine has started!';
} else {
button.value = 'Start machine';
paragraph.textContent = 'The machine is stopped.';
}
}
The script gets a reference to the
HTMLInputElement
object representing the
<input>
in the DOM, saving this refence in the variable
button
.
addEventListener()
is then used to establish a function that will be run when
click
events occur on the button.
Keyboard shortcuts, also known as access keys and keyboard equivalents, let the user trigger a button using a key or combination of keys on the keyboard. To add a keyboard shortcut to a button — just as you would with any
<input>
for which it makes sense — you use the
accesskey
全局属性。
在此范例中， s is specified as the access key (you'll need to press s plus the particular modifier keys for your browser/OS combination; see accesskey for a useful list of those).
<form> <input type="button" value="Start machine" accesskey="s"> </form> <p>The machine is stopped.</p>
const button = document.querySelector('input');
const paragraph = document.querySelector('p');
button.addEventListener('click', updateButton);
function updateButton() {
if (button.value === 'Start machine') {
button.value = 'Stop machine';
paragraph.textContent = 'The machine has started!';
} else {
button.value = 'Start machine';
paragraph.textContent = 'The machine is stopped.';
}
}
注意 : The problem with the above example of course is that the user will not know what the access key is! In a real site, you'd have to provide this information in a way that doesn't intefere with the site design (for example by providing an easily accessible link that points to information on what the site accesskeys are).
To disable a button, simply specify the
被禁用
global attribute on it, like so:
<input type="button" value="Disable me" disabled>
You can enable and disable buttons at run time by simply setting
被禁用
to
true
or
false
. In this example our button starts off enabled, but if you press it, it is disabled using
button.disabled = true
。
setTimeout()
function is then used to reset the button back to its enabled state after two seconds.
<input type="button" value="Enabled">
const button = document.querySelector('input');
button.addEventListener('click', disableButton);
function disableButton() {
button.disabled = true;
button.value = 'Disabled';
window.setTimeout(function() {
button.disabled = false;
button.value = 'Enabled';
}, 2000);
}
若
被禁用
attribute isn't specified, the button inherits its
被禁用
state from its parent element. This makes it possible to enable and disable groups of elements all at once by enclosing them in a container such as a
<fieldset>
element, and then setting
被禁用
on the container.
The example below shows this in action. This is very similar to the previous example, except that the
被禁用
attribute is set on the
<fieldset>
when the first button is pressed — this causes all three buttons to be disabled until the two second timeout has passed.
<fieldset> <legend>Button group</legend> <input type="button" value="Button 1"> <input type="button" value="Button 2"> <input type="button" value="Button 3"> </fieldset>
const button = document.querySelector('input');
const fieldset = document.querySelector('fieldset');
button.addEventListener('click', disableButton);
function disableButton() {
fieldset.disabled = true;
window.setTimeout(function() {
fieldset.disabled = false;
}, 2000);
}
注意
: Firefox will, unlike other browsers, by default,
persist the dynamic disabled state
的
<button>
across page loads. Use the
autocomplete
attribute to control this feature.
Buttons don't participate in constraint validation; they have no real value to be constrained.
The below example shows a very simple drawing app created using a
<canvas>
element and some simple CSS and JavaScript (we'll hide the CSS for brevity). The top two controls allow you to choose the color and size of the drawing pen. The button, when clicked, invokes a function that clears the canvas.
<div class="toolbar"> <input type="color" aria-label="select pen color"> <input type="range" min="2" max="50" value="30" aria-label="select pen size"><span class="output">30</span> <input type="button" value="Clear canvas"> </div> <canvas class="myCanvas"> <p>Add suitable fallback here.</p> </canvas>
body {
background: #ccc;
margin: 0;
overflow: hidden;
}
.toolbar {
background: #ccc;
width: 150px;
height: 75px;
padding: 5px;
}
input[type="color"], input[type="button"] {
width: 90%;
margin: 0 auto;
display: block;
}
input[type="range"] {
width: 70%;
}
span {
position: relative;
bottom: 5px;
}
var canvas = document.querySelector('.myCanvas');
var width = canvas.width = window.innerWidth;
var height = canvas.height = window.innerHeight-85;
var ctx = canvas.getContext('2d');
ctx.fillStyle = 'rgb(0,0,0)';
ctx.fillRect(0,0,width,height);
var colorPicker = document.querySelector('input[type="color"]');
var sizePicker = document.querySelector('input[type="range"]');
var output = document.querySelector('.output');
var clearBtn = document.querySelector('input[type="button"]');
// covert degrees to radians
function degToRad(degrees) {
return degrees * Math.PI / 180;
};
// update sizepicker output value
sizePicker.oninput = function() {
output.textContent = sizePicker.value;
}
// store mouse pointer coordinates, and whether the button is pressed
var curX;
var curY;
var pressed = false;
// update mouse pointer coordinates
document.onmousemove = function(e) {
curX = (window.Event) ? e.pageX : e.clientX + (document.documentElement.scrollLeft ? document.documentElement.scrollLeft : document.body.scrollLeft);
curY = (window.Event) ? e.pageY : e.clientY + (document.documentElement.scrollTop ? document.documentElement.scrollTop : document.body.scrollTop);
}
canvas.onmousedown = function() {
pressed = true;
};
canvas.onmouseup = function() {
pressed = false;
}
clearBtn.onclick = function() {
ctx.fillStyle = 'rgb(0,0,0)';
ctx.fillRect(0,0,width,height);
}
function draw() {
if(pressed) {
ctx.fillStyle = colorPicker.value;
ctx.beginPath();
ctx.arc(curX, curY-85, sizePicker.value, degToRad(0), degToRad(360), false);
ctx.fill();
}
requestAnimationFrame(draw);
}
draw();
| 规范 | 状态 | 注释 |
|---|---|---|
|
HTML 实时标准
The definition of '<input type="button">' in that specification. |
实时标准 | |
|
HTML5
The definition of '<input type="button">' in that specification. |
推荐 |
| 桌面 | 移动 | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
type="button"
|
Chrome 完整支持 1 | Edge 完整支持 12 | Firefox 完整支持 1 | IE 完整支持 Yes | Opera 完整支持 Yes | Safari 完整支持 1 | WebView Android 完整支持 Yes | Chrome Android 完整支持 18 | Firefox Android 完整支持 4 | Opera Android 完整支持 Yes | Safari iOS 完整支持 Yes | Samsung Internet Android 完整支持 1.0 |
完整支持
<input>
和
HTMLInputElement
interface which implements it.
<button>
元素。
<button>
<datalist>
<fieldset>
<form>
<input>
<label>
<legend>
<meter>
<optgroup>
<option>
<output>
<progress>
<select>
<textarea>
<input>
类型
<input type="button">
<input type="checkbox">
<input type="color">
<input type="date">
<input type="datetime">
<input type="datetime-local">
<input type="email">
<input type="file">
<input type="hidden">
<input type="image">
<input type="month">
<input type="number">
<input type="password">
<input type="radio">
<input type="range">
<input type="reset">
<input type="search">
<input type="submit">
<input type="tel">
<input type="text">
<input type="time">
<input type="url">
<input type="week">