jQuery $美元符号
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/1180213/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
The $ dollar sign
提问by Mark
I have something simple like this:
我有这样简单的事情：
$(selector).append("somestuff");
But since I'm going to reuse the selector I cache it with:
但是由于我要重用选择器，所以我将它缓存为：
var $selector = $(selector);
So I end up with:
所以我最终得到：
$selector.append("somestuff");
My question is, should I be doing that, or should I be doing:
我的问题是，我应该这样做，还是应该这样做：
var selector = $(selector);
selector.append("somestuff");
Trying either one, both works. Which method is correct, and why? Is the $in $selectorunnecessary because the jquery object has already been declared in $(selector)?
尝试任何一种，都有效。哪种方法是正确的，为什么？是$在$selector不必要的，因为jQuery对象已经在申报$(selector)？
Edit
编辑
Thanks for the answers. It seems very simple and quite clear. Still, there seems to be disagreement over whether or not I should use $in the variable. It would be nice for everyone to vote up an answer. :)
感谢您的回答。这看起来很简单，也很清楚。尽管如此，对于我是否应该$在变量中使用似乎存在分歧。每个人都投票赞成答案会很好。:)
采纳答案by Michael Morton
I've seen it done both ways. All you are doing is creating a variable with the name '$selector', so they are functionally equivalent. The nice thing about it is that it does make them easy to pick out as jQuery objects.
我已经看到它以两种方式完成。您所做的只是创建一个名为“$selector”的变量，因此它们在功能上是等效的。它的好处是它确实使它们很容易被挑选为 jQuery 对象。
回答by RichieHindle
$is just a name - names in JavaScript can contain dollar signs, and can consist of just a dollar sign.
$只是一个名字 - JavaScript 中的名字可以包含美元符号，并且可以只包含一个美元符号。
Whether you use a dollar sign in your name isn't relevant to jQuery - there's nothing special about the dollar sign, except that jQuery defines a function called $.
是否在名称中使用美元符号与 jQuery 无关 - 美元符号没有什么特别之处，只是 jQuery 定义了一个名为$.
回答by Ben Crouse
The cash sign is just an alias for the jQuery function. Starting the variable name with $ has no effect on that variable.
现金符号只是 jQuery 函数的别名。以 $ 开头的变量名对该变量没有影响。
It is customary though, especially in jQuery plugin development, to use variables already wrapped in jQuery with a cash sign, so you know you can call jQuery methods, without having to wrap them.
不过，习惯上，尤其是在 jQuery 插件开发中，使用已经包装在 jQuery 中的带有现金符号的变量，因此您知道您可以调用 jQuery 方法，而无需包装它们。
回答by thedz
RichieHindle is correct. To expand:
RichieHindle 是正确的。扩张：
Javascript variables allow the '$' character. So for example, you could have the following:
Javascript 变量允许使用 '$' 字符。因此，例如，您可以具有以下内容：
var $i = 1;
var i = 1;
Both i and $i have the same value, and both are perfectly legitimate variable names.
i 和 $i 具有相同的值，并且都是完全合法的变量名。
jQuery assigns itself (the jQuery object) to '$' because traditionally, that's what Javascript frameworks have done for selectors. There's no inherent meaning to '$' beyond what jQuery gives it.
jQuery 将自身（jQuery 对象）分配给 '$'，因为传统上，这是 Javascript 框架为选择器所做的。'$' 除了 jQuery 赋予的意义之外，没有任何内在的意义。
回答by mkoryak
I like to prefix all my jQuery object names with $so that I know it's actually a jQuery object, not a DOM reference.
我喜欢在我所有的 jQuery 对象名称前加上前缀，$这样我就知道它实际上是一个 jQuery 对象，而不是一个 DOM 引用。
It's a good naming convention.
这是一个很好的命名约定。
回答by Zachary K
In this case, $selectoris an example of Hungarian notation. It is there so that you know that $selectoris a jQuery object.
在这种情况下，$selector是匈牙利符号的一个例子。它在那里，以便您知道这$selector是一个 jQuery 对象。
If you make it your custom to always have jQuery objects start with $if you suddenly use one wrong it will look wrong which will help you find a problem in your code.
如果您习惯于始终以 jQuery 对象开头，$如果您突然使用了一个错误，它看起来会出错，这将帮助您找到代码中的问题。
The language couldn't care less. They could have just as well named the jQuery function Jor anything else; the $is not a special symbol.
语言根本不在乎。他们也可以命名 jQuery 函数J或其他任何东西；在$不是特殊符号。
回答by easement
Yeah.
是的。
jQuery always returns a jQuery object. It's what allows chaining.
jQuery 总是返回一个 jQuery 对象。这就是允许链接的原因。
You've already defined the variable so you get a jQuery object back so $ is unnecessary
你已经定义了变量，所以你得到了一个 jQuery 对象，所以 $ 是不必要的
回答by Grant Heaslip
I don't believe that you need to add the jQuery selector to jQuery objects (since it's already a part of the object). We don't add the selector and haven't run into any problems.
我不认为您需要将 jQuery 选择器添加到 jQuery 对象（因为它已经是对象的一部分）。我们没有添加选择器，也没有遇到任何问题。
回答by vh.
"$" is a function in jQuery. So when you call $(selector), you're actually calling the function $with selectoras the argument.
"$" 是 jQuery 中的一个函数。所以，当你调用$（选择），你实际上调用该函数$以selector作为参数。
Generally, don't use the "$" as part of a variable name for javascript. You will only confuse yourself.
通常，不要使用“$”作为 javascript 变量名的一部分。你只会迷惑自己。
