Category: Properties of jQuery Object Instances
.context
The DOM node context originally passed to jQuery(); if none was passed then context will likely be the document.
.jquery
A string containing the jQuery version number.
.length
The number of elements in the jQuery object.
.selector
A selector representing selector passed to jQuery(), if any, when creating the original set.
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https://api.jquery.com/category/properties/jquery-object-instance-properties