我试图在创建特定 div 时关闭一个函数。用最简单的术语来说，我有这样的事情：
<a href="" id="foo">Click me!</a>
<script>
$("#foo").live("click",function(e) {
e.preventDefault();
$(this).append($("<div />").html("new div").attr("id","bar"));
});
</script>
之前，我有突变事件监听 div#bar 的创建 - 像这样：
$("#bar").live("DOMNodeInserted", function(event) {
console.log("a new div has been appended to the page");
});
是否有使用 Mutation Observers 的等价物？我在 DOM 元素的样式对象更改后是否有一个 javascript 钩子触发器？但该插件仅检测元素何时被修改，而不是在创建时检测。
这是用于侦听子列表 of 上的突变#foo并检查是否添加了具有 id 的子项的代码bar。
MutationObserver = window.MutationObserver || window.WebKitMutationObserver;
$("#foo").live("click",function(e) {
e.preventDefault();
$(this).append($("<div />").html("new div").attr("id","bar"));
});
// define a new observer
var obs = new MutationObserver(function(mutations, observer) {
// look through all mutations that just occured
for(var i=0; i<mutations.length; ++i) {
// look through all added nodes of this mutation
for(var j=0; j<mutations[i].addedNodes.length; ++j) {
// was a child added with ID of 'bar'?
if(mutations[i].addedNodes[j].id == "bar") {
console.log("bar was added!");
}
}
}
});
// have the observer observe foo for changes in children
obs.observe($("#foo").get(0), {
childList: true
});
然而，这只观察到#foo。如果你想寻找#bar作为其他节点的新子节点的添加，你需要通过额外的调用来观察那些潜在的父节点obs.observe()。要观察 id 为 的节点baz，您可以执行以下操作：
obs.observe($('#baz').get(0), {
childList: true,
subtree: true
});
添加的subtree选项意味着观察员将寻找另外的#bar无论是作为孩子或更深的后裔（如孙子）。
使用 jQuery 时，可以简化MutationObserver的用法，如下所示。
$("#btnAddDirectly").click(function () {
$("#canvas").append($('<span class="stuff">new child direct</span>'));
});
$("#btnAddAsChildOfATree").click(function () {
$("#canvas").append($('<div><div><span class="stuff">new child tree</span></div></div>'));
});
var obs = new MutationObserver(function(mutations, observer) {
// using jQuery to optimize code
$.each(mutations, function (i, mutation) {
var addedNodes = $(mutation.addedNodes);
var selector = "span.stuff"
var filteredEls = addedNodes.find(selector).addBack(selector); // finds either added alone or as tree
filteredEls.each(function () { // can use jQuery select to filter addedNodes
alert('Insertion detected: ' + $(this).text());
});
});
});
var canvasElement = $("#canvas")[0];
obs.observe(canvasElement, {childList: true, subtree: true});<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="canvas">
Canvas
</div>
<button id="btnAddDirectly">Add span directly to canvas</button>
<button id="btnAddAsChildOfATree">Add span as child of a tree</button>不要忘了，第二个参数.observe()，MutationObserverInit是很重要的：
在选项中，使用childList: trueifspan将仅作为直接子项添加。subTree: true如果它可以在任何级别以下#canvas。
从文档：
childList: 设置为true是否要观察目标节点的子元素（包括文本节点）的添加和删除。subtree：true如果要观察到目标和目标的后代的突变，则设置为。突变观察者
// Select the node that will be observed for mutations
const targetNode = document.getElementById('some-id');
// Options for the observer (which mutations to observe)
const config = { attributes: true, childList: true, subtree: true };
// Callback function to execute when mutations are observed
const callback = function(mutationsList, observer) {
// Use traditional 'for loops' for IE 11
for(const mutation of mutationsList) {
if (mutation.type === 'childList') {
console.log('A child node has been added or removed.');
}
else if (mutation.type === 'attributes') {
console.log('The ' + mutation.attributeName + ' attribute was modified.');
}
}
};
// Create an observer instance linked to the callback function
const observer = new MutationObserver(callback);
// Start observing the target node for configured mutations
observer.observe(targetNode, config);
// Later, you can stop observing
observer.disconnect();
https://developer.mozilla.org/en-US/docs/Web/API/MutationObserver