var $this = $(this)

亦凉 2021-11-29 18:56 281阅读 0赞

# [jQuery: What’s the Difference Between $(this), $this, and this?][jQuery_ What_s the Difference Between _this_ _this_ and this] #

### What about $this? ###

$this is a little different because it’s actually just a variable that uses the $. It has no inherent relation to jQuery.

It would be no different than JavaScript variables named $corn or $carrots.

You just was easily say var $this = “My pet cat is named Mittens.”; It’s just a variable with the dollar sign in it.

JavaScript allows characters like this in variable names.

The reason that you see use of $this inside of jQuery plugins is that often times developers in the global scope **inside of their plugin** will say something like:

var $this = $(this);

That way they can always have a reference to the object on which the plugin was called.

The scope of “this” will change in any methods used inside the plugin so it’s always good to have a global variable (that is, global inside the plugin scope) which you can refer to the object on which the plugin was called.

But the important thing to remember is that $this has no inherent relation to jQuery. It’s just a variable like any other.

# [What is the reason for var $this = this][What is the reason for var _this _ this] #

Generally, this means a copy of `this`. The thing about `this` is that it changes within each function.

Storing it this way, however, keeps `$this` from changing whereas `this` does change.

jQuery heavily uses the magic `this` value.

Consider this code, where you might need something like you are seeing:

$.fn.doSomethingWithElements = function() {
        var $this = this;
    
        this.each(function() {
            // `this` refers to each element and differs each time this function
            //    is called
            //
            // `$this` refers to old `this`, i.e. the set of elements, and will be
            //    the same each time this function is called
        });
    };

# [https://blog.csdn.net/mxt123456/article/details/53152398][https_blog.csdn.net_mxt123456_article_details_53152398] #

在很多地方，我们都会看到  
var $this = $(this)的代码，那它到底是什么意思，有什么用呢？

this其实是一个html 元素。  
$this 只是个变量名，加$前缀是为说明其是个jquery对象。  
而$(this)是个转换，将this表示的dom对象转为jquery对象，这样就可以使用jquery提供的方法操作。

作用：把当前对象保存起来，便于后边的使用。

转载于:https://www.cnblogs.com/chucklu/p/11164158.html

[jQuery_ What_s the Difference Between _this_ _this_ and this]: http://www.9bitstudios.com/2013/03/jquery-whats-the-difference-between-this-this-and-this/%20
[What is the reason for var _this _ this]: https://stackoverflow.com/questions/7234282/what-is-the-reason-for-var-this-this
[https_blog.csdn.net_mxt123456_article_details_53152398]: https://blog.csdn.net/mxt123456/article/details/53152398