jQuery.parent(expr) To find the parent node, you can pass in expr for filtering, such as $("span").parent() or $("span").parent(".class")
jQuery .parents(expr), similar to jQuery.parents(expr), but searches for all ancestor elements, not limited to parent elements
jQuery.children(expr). Returns all child nodes. This method will only return direct The child nodes will not return all descendant nodes
jQuery.contents(), but return all the content below, including nodes and text. The difference between this method and children() is that, including blank text, it will also be returned as a
jQuery object, while children() will only return the node
jQuery.prev(), Returns the previous sibling node, not all sibling nodes
jQuery.prevAll(), returns all previous sibling nodes
jQuery.next(), returns the next sibling node, not all Sibling nodes
jQuery.nextAll(), returns all subsequent sibling nodes
jQuery.siblings(), returns sibling nodes, regardless of before or after
jQuery.find( expr), which is completely different from jQuery.filter(expr). jQuery.filter() filters out a part of the initial collection of jQuery objects, and the return result of jQuery.find() will not contain the contents of the initial collection, such as $("p"), find("span") , starting from the element, equivalent to $("p span")