document.getElementbyId与简写（Id.someMethod） [英] document.getElementbyId vs. shorthand (Id.someMethod)

问题描述

当您只能使用简写 Id.something 时，写出 document.getElementById 是否有任何好处？我很感兴趣，因为我在教程中看到一些代码，声明变量 x 等于 document.getElementById ，然后他们使用该变量，而不仅仅是使用简写：

Is there any advantage to writing out document.getElementById when you can just use the shorthand Id.something? I'm interested because I see some code online in my tutorials declaring variable x equals to document.getElementById, and then them using that variable, instead of just using the shorthand:

示例：

<code>
    var timeDisplay = document.getElementById("time");
    timeDisplay.innerHTML = message;
</code>

VS.

<code>
    time.innerHTML = message;
</code>

推荐答案

扩展我的评论，你永远不应该使用简写因为它很危险而且令人困惑。

Expanding on my comment, you should never use the "shorthand" because it is dangerous and confusing.

这是危险的，因为其他人可以在代码执行之前定义 window.time 属性，现在你的整个代码中断：

It is dangerous because someone else can defined the window.time property before your code gets executed, and now your entire code breaks:

// some one put this in the global scope
var time = new Date();

// your code
time.innerHTML = message; // nope!

https://jsfiddle.net/DerekL/6yz8j7dx/

这甚至不是主观选择。这是你几乎永远不会做 time.something 。

It isn't even about subjective choices. It's that you should almost never do time.something.

关于为什么令人困惑的奖金示例：

Bonus example on why it is confusing:

<div id="history"></div>

history.textContent = "Will it work?";

猜猜会发生什么？

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