为元素赋值

发布于 2024-10-12 22:25:01 字数 372 浏览 1 评论 0原文

我想知道是否可以为元素对象赋值。在本例中，我希望将 setTimeout() 函数的返回值分配给元素对象中的对象。

例如：

var elem = document.getElementById('target');
elem.timeouts = new Object();
elem.timeouts.sometimeout = setTimeout('...', 1000);

所以我可以这样做：

clearTimeout(elem.timeouts.sometimeout);

我知道这可能看起来很糟糕，但是否有可能或会导致浏览器着火并打开用户等。

谢谢。

原文

I was wondering if it was possible to assign values to an element object. In this case, I wish to assign the returns from the setTimeout() function to an object within an element object.

For example:

var elem = document.getElementById('target');
elem.timeouts = new Object();
elem.timeouts.sometimeout = setTimeout('...', 1000);

So I could then do:

clearTimeout(elem.timeouts.sometimeout);

I know this might seem bad practice etc, but is it possible or will it cause browsers to catch fire and turn on their user etc.

Thanks.

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苏辞 2024-10-19 22:25:01

DOM 元素是宿主对象（又名非本机），因此它们几乎可以做任何想做的事情。不保证您的 Expando 能够正常工作。特别是 IE 曾经遇到过问题。强烈建议阅读这篇文章：

扩展 DOM 有什么问题< /a> 作者：@kangax
（来自一位经历过这种坏习惯的缺点的 Prototype.js 开发人员。他们重写了整个库，只是为了让自己免于更多的麻烦）

现在，如果您添加 uniqueID 到非 IE 浏览器中的元素（IE 默认情况下有它），然后您的 data 函数就变成了一个简单的查找 ~ O(1)。真实信息将存储在闭包中。

它比 jQuery.data 快 2-4 倍 (test)

data(elem, "key", "value");

1.) 哈希表

var data = (function () {
    var storage = {};
    var counter = 1;
    return function (el, key, value) {
        var uid = el.uniqueID || (el.uniqueID = counter++);
        if (typeof value != "undefined") {
            storage[uid] || (storage[uid] = {});
            storage[uid][key] = value; // set
        } else if (storage[uid]) {
            return storage[uid][key]; // get
        }
    };
})();

2.) 数组

如果你想避免同时扩展，你可以使用数组来保存elements （但速度较慢）

var data = (function () {
    var elements = [];
    var storage = [];
    return function (el, key, value) {
        var i = elements.indexOf(el);
        if (typeof value != "undefined") {
            if (i == -1) {
                i = elements.length;
                elements[i] = el;
                storage[i] = {};
            }
            storage[i][key] = value; // set
        } else if (storage[i]) {
            return storage[i][key]; // get
        }
    };
})();

Array.prototype.indexOf （后备）

if (!Array.prototype.indexOf) {
    Array.prototype.indexOf = function (item) {
        var len = this.length >>> 0;
        for (var i = 0; i < len; i++) {
            if (this[i] === item) {
                return i;
            }
        }
        return -1;
    };
}

不客气！ :)

DOM elements are Host objects (aka non-native) and as such they can do almost anything they want. It's not guaranteed that your expandos will work. In particular IE used to have problems with them. It's highly recommended to read this article:

What’s wrong with extending the DOM by @kangax
(it is from one of the Prototype.js developers who experienced the drawbacks of such bad habits. They've rewritten the whole library just to save themselfs from more headaches)

Now if you add uniqueID to elements in non-IE browsers (IE has it by default) and then your data function becomes a simple lookup ~ O(1). The real information will be stored in a closure.

It's 2-4x faster than jQuery.data (test)

data(elem, "key", "value");

1.) Hash table

var data = (function () {
    var storage = {};
    var counter = 1;
    return function (el, key, value) {
        var uid = el.uniqueID || (el.uniqueID = counter++);
        if (typeof value != "undefined") {
            storage[uid] || (storage[uid] = {});
            storage[uid][key] = value; // set
        } else if (storage[uid]) {
            return storage[uid][key]; // get
        }
    };
})();

2.) Array

If you want to avoid expandos all together you can use an array to hold elements (but it's slower)

var data = (function () {
    var elements = [];
    var storage = [];
    return function (el, key, value) {
        var i = elements.indexOf(el);
        if (typeof value != "undefined") {
            if (i == -1) {
                i = elements.length;
                elements[i] = el;
                storage[i] = {};
            }
            storage[i][key] = value; // set
        } else if (storage[i]) {
            return storage[i][key]; // get
        }
    };
})();

Array.prototype.indexOf (fallback)

if (!Array.prototype.indexOf) {
    Array.prototype.indexOf = function (item) {
        var len = this.length >>> 0;
        for (var i = 0; i < len; i++) {
            if (this[i] === item) {
                return i;
            }
        }
        return -1;
    };
}

You're welcome! :)

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