**(1) basic object acquisition ** $(” * ”) Get all objects

$(” # element ”) Getting an object with id element is equivalent to document.getelementbyid (” element ”);

$(” ABC ”) Gets the object with class ABC

$(” div ”) Gets all the div elements in the HTML

$(“#a,.b, p”) Get id a and class b and all the p elements

$(” # a. b p ”) Gets the p element under id a and class under b

(2) hierarchical object acquisition

$(” div> Input ”) Gets all the input objects under div

$(” div + h ”) Gets an h element immediately after the div

$(” div ~ p ”) Gets all the p elements after the element div

(3) simple object acquisition

$(” element: first ”) Gets the first $(“div:frist”) of an element on the page to denote the first div

$(” element: the last ”) Gets the last element on the page such as $(“div:frist”) for the last div

$(” element: not selector () ”) Remove all elements that match the selector such as $(“input:not(:check)”) to indicate all unselected check boxes

$(” element: even ”) Gets the even number of rows of the element element

$(” element: odd ”) Gets the odd row of the element

$(” element: eq (index) ”) Gets the element of a particular index such as $(“div:el(2)”) for the third div

$(” element: gt (index) ”) Matches all elements greater than the given index value

$(” element: lt (index) ”) Matches all elements less than a given index

$(” : the header ”) The element that matches the h tag

$(” element: animated ”) Matches all elements that are not animated

(4) acquisition of content objects and visibility of objects

$(” Element: the contains (text) ”) Whether the text in the element contains a letter or a string

$(” Element: the empty ”) Gets an element object that contains no text or child elements

$(” Element: the parent ”) Gets that the object element contains text or child elements

$(” Element: from (the selector) ”) Matching whether an element contains an element such as $(“p:has(span)”) indicates all p elements that contain a span element

$(” Element: hidden ”) Matching all invisible elements, including display:none and the input property is the hidden element

$(” Element: the visible ”) Match all courseware elements

(5) object to obtain advanced order

$(” Element [id] ”) Gets all elements with an id attribute

$(” Element/attribute = the abcd ”) Gets all elements with an attribute of abcd

$(” Element/attribute! = the abcd ”) Gets all elements whose attribute is not abcd

$(” Element/attribute ^ = ab] ”) Gets all elements with an attribute beginning with ab

$(” Element/attribute $= ab ”) Gets all elements whose attributes end in ab

$(” Element/attribute * = ab ”) Gets all elements that have an attribute containing ab

$(” Element [selector1] [selector2] […]. ”) Matching an attribute selector such as $(“input[id][name][value=abcd]”) means getting an input element with an id, name, and value as abcd

(6) acquisition of child elements

$(” Element: the NTH - the child (index) ”) Select the NTH child of the parent element, starting at 1 : the NTH - child (even) even Odd: NTH - child (odd) : the NTH - child (3 n) expression : the NTH - child (2) index : the NTH - child (3 n + 1) expression

$(” Element: first - the child ”) The first child element under the parent level

$(” Element: the last - the child ”) The last child element under the parent level

$(” Element: only - child ”) The only child element under the parent level

(7) get the form object

$(input) Only the input element of type input button select textarea can be matched

: $(text) All when line text boxes

$(password) All password boxes

: $(radio) All radio buttons

$(: checkbox) All check boxes

$(: submit) All submit buttons

$(image) All image fields $(reset) All recharge buttons

$(: the button) All buttons

$(: file) All file upload fields

$(hidden) All invisible or hidden elements

$(enabled) All available input elements

: $(disabled) All unavailable input elements

$(checked) All check box elements

$(selected) All the drop-down lists

(8) setting and removing of element attributes

$(” Element ”). Attr (name) Gets the attribute value of the first matched element such as $(“img”).attr(” SRC ”);

$(” Element ”). Attr ({key: value, the key: value,… }) Set multiple attributes for an element at once

$(” Element ”). Attr (key, value) Sets properties for an element

$(” Element ”). Attr (key, the function) Sets a computed attribute for all matched elements

$(” Element ”). RemoveAttr (name) Removes an attribute