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>