The origin of the $ symbol in jQuery

$ is a famous jQuery symbol. In fact, jQuery encapsulates all functions in a global variable jQuery, and $ is also a legal variable name. It is an alias of the variable jQuery:

• window.jQuery ; // jQuery(selector, context)

• ##window.$; // jQuery(selector, context)

##$ === jQuery ; // true

• ##typeof($); // 'function'

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  $ is essentially a function, but the function It is also an object, so in addition to being directly called, $ can also have many other attributes.

Note: The $function name you see may not be jQuery(selector, context), because many JavaScript compression tools can rename function names and parameters, so the compressed jQuery source code $function may become a(b,c).

Most of the time, we use $ directly (because it is easier to write). However, if the $ variable is unfortunately occupied and cannot be changed, then we can only ask jQuery to hand over the $ variable, and then we can only use the jQuery variable:

• ##jQuery.noConflict();

• ##$; // undefined

• jQuery; // jQuery(selector, context)

• The principle of this black magic is that jQuery saves the original internally before occupying $ $, when calling jQuery.noConflict(), the originally saved variables will be restored

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