我已使用addEventListener将事件附加到文本框。它工作正常。当我想以编程方式从另一个函数触发事件时，我的问题出现了。
我该怎么做？
您可以在IE 8或更低版本上使用fireEvent，在大多数其他浏览器上使用W3C的dispatchEvent。要创建要触发的事件，可以使用createEvent或createEventObject，具体取决于浏览器。
这是一段不言自明的代码（来自原型），在dataavailable上触发事件element：
var event; // The custom event that will be created
if(document.createEvent){
event = document.createEvent("HTMLEvents");
event.initEvent("dataavailable", true, true);
event.eventName = "dataavailable";
element.dispatchEvent(event);
} else {
event = document.createEventObject();
event.eventName = "dataavailable";
event.eventType = "dataavailable";
element.fireEvent("on" + event.eventType, event);
}
function fireMouseEvent(obj, evtName) {
if (obj.dispatchEvent) {
//var event = new Event(evtName);
var event = document.createEvent("MouseEvents");
event.initMouseEvent(evtName, true, true, window,
0, 0, 0, 0, 0, false, false, false, false, 0, null);
obj.dispatchEvent(event);
} else if (obj.fireEvent) {
event = document.createEventObject();
event.button = 1;
obj.fireEvent("on" + evtName, event);
obj.fireEvent(evtName);
} else {
obj[evtName]();
}
}
var obj = document.getElementById("......");
fireMouseEvent(obj, "click");
你可以使用我编译在一起的这个功能。
if (!Element.prototype.trigger)
{
Element.prototype.trigger = function(event)
{
var ev;
try
{
if (this.dispatchEvent && CustomEvent)
{
ev = new CustomEvent(event, {detail : event + ' fired!'});
this.dispatchEvent(ev);
}
else
{
throw "CustomEvent Not supported";
}
}
catch(e)
{
if (document.createEvent)
{
ev = document.createEvent('HTMLEvents');
ev.initEvent(event, true, true);
this.dispatchEvent(event);
}
else
{
ev = document.createEventObject();
ev.eventType = event;
this.fireEvent('on'+event.eventType, event);
}
}
}
}
触发以下事件：
var dest = document.querySelector('#mapbox-directions-destination-input');
dest.trigger('focus');
观看活动：
dest.addEventListener('focus', function(e){
console.log(e);
});
希望这可以帮助！
您可以使用以下代码使用Element方法触发事件：
if (!Element.prototype.triggerEvent) {
Element.prototype.triggerEvent = function (eventName) {
var event;
if (document.createEvent) {
event = document.createEvent("HTMLEvents");
event.initEvent(eventName, true, true);
} else {
event = document.createEventObject();
event.eventType = eventName;
}
event.eventName = eventName;
if (document.createEvent) {
this.dispatchEvent(event);
} else {
this.fireEvent("on" + event.eventType, event);
}
};
}
if (!Element.prototype.triggerEvent) {
Element.prototype.triggerEvent = function (eventName) {
var event;
if (document.createEvent) {
event = document.createEvent("HTMLEvents");
event.initEvent(eventName, true, true);
} else {
event = document.createEventObject();
event.eventType = eventName;
}
event.eventName = eventName;
if (document.createEvent) {
this.dispatchEvent(event);
} else {
this.fireEvent("on" + event.eventType, event);
}
};
}
var input = document.getElementById("my_input");
var button = document.getElementById("my_button");
input.addEventListener('change', function (e) {
alert('change event fired');
});
button.addEventListener('click', function (e) {
input.value = "Bye World";
input.triggerEvent("change");
});<input id="my_input" type="input" value="Hellow World">
<button id="my_button">Change Input</button>最有效的方法是调用直接在addEventListener注册的相同函数。
您还可以使用CustomEvent和co触发假事件。
最后一些元素，如<input type="file">支持.click()方法。
var btn = document.getElementById('btn-test');
var event = new Event(null);
event.initEvent('beforeinstallprompt', true, true);
btn.addEventListener('beforeinstallprompt', null, false);
btn.dispatchEvent(event);
这将imediattely触发事件'beforeinstallprompt'
使用jquery事件调用。在下面的行中写下要触发任何元素的onChange。
$("#element_id").change();
element_id是要触发其onChange的元素的ID。
避免使用
element.fireEvent("onchange");
因为它的支持很少。请参阅此文档以获取其support。
HTML
<a href="demoLink" id="myLink"> myLink </a>
<button onclick="fireLink(event)"> Call My Link </button>
JS
// click event listener of the link element --------------
document.getElementById('myLink').addEventListener("click", callLink);
function callLink(e) {
// code to fire
}
// function invoked by the button element ----------------
function fireLink(event) {
document.getElementById('myLink').click(); // script calls the "click" event of the link element
}
你想要的是这样的：
document.getElementByClassName("example").click();
使用jQuery，它将是这样的：
$(".example").trigger("click");
一个工作的例子：
// Add an event listener
document.addEventListener("name-of-event", function(e) {
console.log(e.detail); // Prints "Example of an event"
});
// Create the event
var event = new CustomEvent("name-of-event", { "detail": "Example of an event" });
// Dispatch/Trigger/Fire the event
document.dispatchEvent(event);
对于旧浏览器polyfill和更复杂的示例，请参阅MDN docs。
请参阅EventTarget.dispatchEvent和CustomEvent的支持表。
如果您不想使用jQuery并且不特别关注向后兼容性，那么只需使用：
let element = document.getElementById(id);
element.dispatchEvent(new Event("change")); // or whatever the event type might be
编辑：根据您的设置，您可能想要添加bubbles: true：
let element = document.getElementById(id);
element.dispatchEvent(new Event('change', { 'bubbles': true }));
如果你使用jQuery，你可以简单地做
$('#yourElement').trigger('customEventName', [arg0, arg1, ..., argN]);
并处理它
$('#yourElement').on('customEventName',
function (objectEvent, [arg0, arg1, ..., argN]){
alert ("customEventName");
});
其中“[arg0，arg1，...，argN]”表示这些参数是可选的。
如果您支持IE9 +，则可以使用以下内容。同样的概念被纳入You Might Not Need jQuery。
function addEventListener(el, eventName, handler) {
if (el.addEventListener) {
el.addEventListener(eventName, handler);
} else {
el.attachEvent('on' + eventName, function() {
handler.call(el);
});
}
}
function triggerEvent(el, eventName, options) {
var event;
if (window.CustomEvent) {
event = new CustomEvent(eventName, options);
} else {
event = document.createEvent('CustomEvent');
event.initCustomEvent(eventName, true, true, options);
}
el.dispatchEvent(event);
}
// Add an event listener.
addEventListener(document, 'customChangeEvent', function(e) {
document.body.innerHTML = e.detail;
});
// Trigger the event.
triggerEvent(document, 'customChangeEvent', {
detail: 'Display on trigger...'
});如果您已经在使用jQuery，那么这里是上面代码的jQuery版本。
$(function() {
// Add an event listener.
$(document).on('customChangeEvent', function(e, opts) {
$('body').html(opts.detail);
});
// Trigger the event.
$(document).trigger('customChangeEvent', {
detail: 'Display on trigger...'
});
});<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>我使用JavaScript在mouseover上搜索了click click，mousedown和mouseup事件。我找到了Juan Mendes提供的答案。要获得答案，请单击here。
点击here是现场演示，下面是代码：
function fireEvent(node, eventName) {
// Make sure we use the ownerDocument from the provided node to avoid cross-window problems
var doc;
if (node.ownerDocument) {
doc = node.ownerDocument;
} else if (node.nodeType == 9) {
// the node may be the document itself, nodeType 9 = DOCUMENT_NODE
doc = node;
} else {
throw new Error("Invalid node passed to fireEvent: " + node.id);
}
if (node.dispatchEvent) {
// Gecko-style approach (now the standard) takes more work
var eventClass = "";
// Different events have different event classes.
// If this switch statement can't map an eventName to an eventClass,
// the event firing is going to fail.
switch (eventName) {
case "click": // Dispatching of 'click' appears to not work correctly in Safari. Use 'mousedown' or 'mouseup' instead.
case "mousedown":
case "mouseup":
eventClass = "MouseEvents";
break;
case "focus":
case "change":
case "blur":
case "select":
eventClass = "HTMLEvents";
break;
default:
throw "fireEvent: Couldn't find an event class for event '" + eventName + "'.";
break;
}
var event = doc.createEvent(eventClass);
var bubbles = eventName == "change" ? false : true;
event.initEvent(eventName, bubbles, true); // All events created as bubbling and cancelable.
event.synthetic = true; // allow detection of synthetic events
// The second parameter says go ahead with the default action
node.dispatchEvent(event, true);
} else if (node.fireEvent) {
// IE-old school style
var event = doc.createEventObject();
event.synthetic = true; // allow detection of synthetic events
node.fireEvent("on" + eventName, event);
}
};
只是建议一个不需要手动调用监听器事件的替代方案：
无论您的事件监听器做什么，都将其移动到一个函数中并从事件监听器调用该函数。
然后，您还可以在其他任何地方调用该函数，以完成事件触发时所执行的操作。
我觉得这不那么“代码密集”，更容易阅读。
我只是使用了以下（似乎更简单）：
element.blur();
element.focus();
在这种情况下，只有当值被真正改变时才会触发事件，正如您通过用户执行的正常聚焦轨迹触发它一样。
修改@ Dorian的answer与IE合作：
document.addEventListener("my_event", function(e) {
console.log(e.detail);
});
var detail = 'Event fired';
try {
// For modern browsers except IE:
var event = new CustomEvent('my_event', {detail:detail});
} catch(err) {
// If IE 11 (or 10 or 9...?) do it this way:
// Create the event.
var event = document.createEvent('Event');
// Define that the event name is 'build'.
event.initEvent('my_event', true, true);
event.detail = detail;
}
// Dispatch/Trigger/Fire the event
document.dispatchEvent(event);