如何向元素添加onload事件?
我可以使用:
<div onload="oQuickReply.swap();" ></div>
对于这个吗?
如何向元素添加onload事件?
我可以使用:
<div onload="oQuickReply.swap();" ></div>
对于这个吗?
当前回答
Onload事件,它只支持下面列出的几个标签。
<body>, <frame>, <iframe>, <img>, <input type="image">, <link>, <script>, <style>
这里是onload事件的引用
其他回答
我们可以使用MutationObserver来有效地解决这个问题,添加下面的示例代码
<!DOCTYPE html>
<html>
<head>
<title></title>
<style>
#second{
position: absolute;
width: 100px;
height: 100px;
background-color: #a1a1a1;
}
</style>
</head>
<body>
<div id="first"></div>
<script>
var callthis = function(element){
element.setAttribute("tabIndex",0);
element.focus();
element.onkeydown = handler;
function handler(){
alert("called")
}
}
var observer = new WebKitMutationObserver(function(mutations) {
mutations.forEach(function(mutation) {
for (var i = 0; i < mutation.addedNodes.length; i++)
if(mutation.addedNodes[i].id === "second"){
callthis(mutation.addedNodes[i]);
}
})
});
observer.observe(document.getElementById("first"), { childList: true });
var ele = document.createElement('div');
ele.id = "second"
document.getElementById("first").appendChild(ele);
</script>
</body>
</html>
试试这个。
. getelementbyid (" div ")。onload = alert("This is a div."); <div id="div">Hello World</div>
试试这个。你需要移除。从oQuickReply.swap()使函数工作。
. getelementbyid (" div ")。onload = oQuickReplyswap(); 函数oQuickReplyswap() { 警报(“Hello World”); } < div id = " div " > < / div >
您可以如下所示附加一个事件侦听器。当选择器#my-id的div完全加载到DOM时,它就会触发。
$(document).on('EventName', '#my-id', function() {
// do something
});
在本例中,EventName可以是'load'或'click'
https://api.jquery.com/on/#on-events-selector-data-handler
避免使用任何基于间隔的方法(因为它们不是性能和准确的),并使用MutationObserver针对动态加载div的父div以获得更好的效率。
更新:这是我写的一个方便的函数。像这样使用它:
onElementLoaded("div.some_class").then(()=>{}).catch(()=>{});
/**
*
* Wait for an HTML element to be loaded like `div`, `span`, `img`, etc.
* ex: `onElementLoaded("div.some_class").then(()=>{}).catch(()=>{})`
* @param {*} elementToObserve wait for this element to load
* @param {*} parentStaticElement (optional) if parent element is not passed then `document` is used
* @return {*} Promise - return promise when `elementToObserve` is loaded
*/
function onElementLoaded(elementToObserve, parentStaticElement) {
const promise = new Promise((resolve, reject) => {
try {
if (document.querySelector(elementToObserve)) {
console.log(`element already present: ${elementToObserve}`);
resolve(true);
return;
}
const parentElement = parentStaticElement
? document.querySelector(parentStaticElement)
: document;
const observer = new MutationObserver((mutationList, obsrvr) => {
const divToCheck = document.querySelector(elementToObserve);
if (divToCheck) {
console.log(`element loaded: ${elementToObserve}`);
obsrvr.disconnect(); // stop observing
resolve(true);
}
});
// start observing for dynamic div
observer.observe(parentElement, {
childList: true,
subtree: true,
});
} catch (e) {
console.log(e);
reject(Error("some issue... promise rejected"));
}
});
return promise;
}
实现细节:
HTML:
<div class="parent-static-div">
<div class="dynamic-loaded-div">
this div is loaded after DOM ready event
</div>
</div>
JS:
var observer = new MutationObserver(function (mutationList, obsrvr) {
var div_to_check = document.querySelector(".dynamic-loaded-div"); //get div by class
// var div_to_check = document.getElementById('div-id'); //get div by id
console.log("checking for div...");
if (div_to_check) {
console.log("div is loaded now"); // DO YOUR STUFF!
obsrvr.disconnect(); // stop observing
return;
}
});
var parentElement = document.querySelector("parent-static-div"); // use parent div which is already present in DOM to maximise efficiency
// var parentElement = document // if not sure about parent div then just use whole 'document'
// start observing for dynamic div
observer.observe(parentElement, {
// for properties details: https://developer.mozilla.org/en-US/docs/Web/API/MutationObserverInit
childList: true,
subtree: true,
});
当你从服务器加载一些html并将其插入DOM树时,你可以使用DOMSubtreeModified,但它已弃用-所以你可以使用MutationObserver或只是直接在loadElement函数中检测新内容,这样你就不需要等待DOM事件
var ignoreFirst=0; var observer = (new MutationObserver((m, ob)=> { if(ignoreFirst++>0) { console.log('Element add on', new Date()); } } )).observe(content, {childList: true, subtree:true }); // simulate element loading var tmp=1; function loadElement(name) { setTimeout(()=>{ console.log(`Element ${name} loaded`) content.innerHTML += `<div>My name is ${name}</div>`; },1500*tmp++) }; loadElement('Michael'); loadElement('Madonna'); loadElement('Shakira'); <div id="content"><div>