Javascript：如何创建全局函数和变量
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Javascript : How to create global functions & variables
提问by Adam
I would like to create a new function that I can use on elements, like this:
我想创建一个可以在元素上使用的新函数，如下所示：
document.getElementById("element").myNewFunction();
I'm not talking about this:
我不是在谈论这个：
document.getElementById("element").myNewFunction = function(){
doSomething...
}
Because this works on that element only, but how should I create global function what I can use on all elements like the ones what are built in to JavaScript?
因为这仅适用于该元素，但是我应该如何创建全局函数，我可以在所有元素（例如 JavaScript 内置的元素）上使用该函数？
回答by Richard H
Use Element's prototype to extend its functionality:
使用 Element 的原型扩展其功能：
Element.prototype.myNewFunction = function() {
// your code...
};
Now you can call this method on any element object.
现在您可以在任何元素对象上调用此方法。
Edit:I've just had a quick check around, and it appears that this will not work for IE7 and below, and IE8 might be iffy.
编辑：我刚刚快速检查了一下，似乎这不适用于 IE7 及更低版本，而 IE8 可能有问题。
Edit 2: Also as Eli points out it's probably not best practice to extend objects you don't own. Given this and shaky IE support you might want to consider a simple procedural function:
编辑 2：正如 Eli 指出的那样，扩展您不拥有的对象可能不是最佳实践。鉴于这个和不稳定的 IE 支持，您可能需要考虑一个简单的过程函数：
function myFunction(element) {
// your code...
// which may or may not return an object or value
return blah;
}
回答by Eli
See this question: In Javascript, can you extend the DOM?.
看到这个问题：在Javascript中，你能扩展DOM吗？.
While it is possible to do, its generally considered bad practice to change the functionality of objects you don't own.
虽然可以这样做，但通常认为更改不属于您的对象的功能是不好的做法。
回答by Zimbabao
Try
尝试
Object.prototype.myNeweFunction=function(){
doSomthing..
}
回答by Free Consulting
For example:
例如：
HTMLAnchorElement.prototype.click = function () {
alert('HAI!');
};
document.links[0].click();
Figure out right object to extend by querying document.getElementById("element").constructor
通过查询找出要扩展的正确对象 document.getElementById("element").constructor
回答by jpsimons
Prototype (the library) does this, extends the native (built-in) DomElement class by adding methods to its prototype. It doesn't work in old IEs though so I'd recommend against it.
Prototype（库）执行此操作，通过向其原型添加方法来扩展本机（内置）DomElement 类。它在旧的 IE 中不起作用，所以我建议不要使用它。
