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  • var $this = $(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

    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

    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。

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  • 原文地址:https://www.cnblogs.com/chucklu/p/11164158.html
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