检测DOM中的更改 [英] Detect changes in the DOM

问题描述

当某些div或输入添加到html中时，我想执行一个函数。
这是可能吗？

I want to execute a function when some div or input are added to the html. Is this possible?

例如，添加一个文本输入，然后应该调用该函数。

For example, a text input is added, then the function should be called.

推荐答案

2015 update，new MutationObserver 现代浏览器支持：

Chrome 18+，Firefox 14+ ，IE 11+，Safari 6 +

如果您需要支持较旧的，您可能会尝试回到其他方法，如这里提到的（！）年龄答复如下。有龙。享受:)

If you need to support older ones, you may try to fall back to other approaches like the ones mentioned in this 5 (!) year old answer below. There be dragons. Enjoy :)

其他人正在更改文档？因为如果您完全控制更改，那么您只需要创建自己的 domChanged API - 具有函数或自定义事件，并在任何地方对其进行触发/调用。

Someone else is changing the document? Because if you have full control over the changes you just need to create your own domChanged API - with a function or custom event - and trigger/call it everywhere you modify things.

DOM Level-2具有突变事件类型 ，但较旧版本的IE不支持。请注意，突变事件是已弃用于DOM3事件规范< a>并具有效能损失。

您可以尝试在IE 中使用 onpropertychange 来模拟突变事件（并返回到粗暴-force方法，如果它们不可用）。

You can try to emulate mutation event with onpropertychange in IE (and fall back to the brute-force approach if non of them is available).

对于一个完整的 dom更改间隔可能是过度杀死。想象一下，您需要存储整个文档的当前状态，并检查每个元素的每个属性是否相同。

For a full domChange an interval could be an over-kill. Imagine that you need to store the current state of the whole document, and examine every element's every property to be the same.

也许如果您只对元素感兴趣和他们的顺序（如你在你的问题中提到的），一个 getElementsByTagName（*）可以工作。如果添加元素，删除元素，替换元素或更改文档的结构，这将自动触发。

Maybe if you're only interested in the elements and their order (as you mentioned in your question), a getElementsByTagName("*") can work. This will fire automatically if you add an element, remove an element, replace elements or change the structure of the document.

我写了一个概念证明：

(function (window) {
    var last = +new Date();
    var delay = 100; // default delay

    // Manage event queue
    var stack = [];

    function callback() {
        var now = +new Date();
        if (now - last > delay) {
            for (var i = 0; i < stack.length; i++) {
                stack[i]();
            }
            last = now;
        }
    }

    // Public interface
    var onDomChange = function (fn, newdelay) {
        if (newdelay) delay = newdelay;
        stack.push(fn);
    };

    // Naive approach for compatibility
    function naive() {

        var last = document.getElementsByTagName('*');
        var lastlen = last.length;
        var timer = setTimeout(function check() {

            // get current state of the document
            var current = document.getElementsByTagName('*');
            var len = current.length;

            // if the length is different
            // it's fairly obvious
            if (len != lastlen) {
                // just make sure the loop finishes early
                last = [];
            }

            // go check every element in order
            for (var i = 0; i < len; i++) {
                if (current[i] !== last[i]) {
                    callback();
                    last = current;
                    lastlen = len;
                    break;
                }
            }

            // over, and over, and over again
            setTimeout(check, delay);

        }, delay);
    }

    //
    //  Check for mutation events support
    //

    var support = {};

    var el = document.documentElement;
    var remain = 3;

    // callback for the tests
    function decide() {
        if (support.DOMNodeInserted) {
            window.addEventListener("DOMContentLoaded", function () {
                if (support.DOMSubtreeModified) { // for FF 3+, Chrome
                    el.addEventListener('DOMSubtreeModified', callback, false);
                } else { // for FF 2, Safari, Opera 9.6+
                    el.addEventListener('DOMNodeInserted', callback, false);
                    el.addEventListener('DOMNodeRemoved', callback, false);
                }
            }, false);
        } else if (document.onpropertychange) { // for IE 5.5+
            document.onpropertychange = callback;
        } else { // fallback
            naive();
        }
    }

    // checks a particular event
    function test(event) {
        el.addEventListener(event, function fn() {
            support[event] = true;
            el.removeEventListener(event, fn, false);
            if (--remain === 0) decide();
        }, false);
    }

    // attach test events
    if (window.addEventListener) {
        test('DOMSubtreeModified');
        test('DOMNodeInserted');
        test('DOMNodeRemoved');
    } else {
        decide();
    }

    // do the dummy test
    var dummy = document.createElement("div");
    el.appendChild(dummy);
    el.removeChild(dummy);

    // expose
    window.onDomChange = onDomChange;
})(window);

用法：

onDomChange(function(){ 
    alert("The Times They Are a-Changin'");
});

这适用于IE 5.5+，FF 2+，Chrome，Safari 3+和Opera 9.6+

This works on IE 5.5+, FF 2+, Chrome, Safari 3+ and Opera 9.6+

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