1. Some of the core methods of JQuery Each (callback) ‘is like a loop $(” Element ”). The length; ‘the number of elements is an attribute $(” Element ”). The size (); ‘is also the number of elements, but having parentheses is a method $(” Element ”). The get (); ‘a collection of elements on a page, stored as an array $(” Element ”). The get (index); The ‘function is the same as above, index is the index of the array $(” Element ”). The get (). The reverse (); ‘take the direction of the resulting array $(” Element1 ”). The index ($(” Element2 ”)); The index value of ‘element 2 in element 1 is.

2. Basic object acquisition (note that all objects obtained here are Jquery objects, not Dom objects, but they can be converted) $(”*”) ‘means to get all the objects but I haven’t used it yet $(“#XXX”) ‘gets the element object with id=XXX (the id can be the id of the tag or the CSS style id) commonly used

$(“input[name=‘username’]”) gets the name=‘username’ element object commonly used in the input tag

$(“.abc”) ‘gets the name of the style class. The element object of ABC is commonly used $(“div”) ‘tag selector selects all div elements commonly used $(“#a,.b,span”) ‘gets the element whose ID is a and the element that USES the class style b and all the span elements $(”# a.bp ”) ‘ID number is a and USES all p elements of the b style

3. Acquisition of hierarchical elements $(” Element1 Element2 Element3…” ) ‘before the parent and after the subset $(” div > P ”) ‘gets all the p elements under div $(“div + p”) the first p element after the ‘div element $(“div ~ p”) all the p elements after the ‘div

4. Simple object acquisition $(“Element:first”) the first Element of a type of Element in a ‘HTML page $(“Element:last”) the last Element of a class of elements in a ‘HTML page $(“Element:not(selector)”) ‘removes all elements that match the given selector, such as $(“input:not(:checked)”) to select all unchecked check boxes $(“Element:even”) ‘gets an even number of rows $(“Element:odd ”) ‘gets an odd number of rows $(“Element:eq(index)”) ‘gets a given index value $(“Element:gt(index)”) ‘gets all the elements after the Element with the given index value $(“Element:lt(index)”) ‘gets all the elements preceding the Element with the given index value

5. Acquisition of content objects and object visibility Contains the text content of text in the $(“Element:contains(text)”) ‘Element $(‘Element:empty”) ‘gets an Element that contains no child elements or text $(“Element:partnt”) ‘gets an Element that contains child elements or text $(“Element:has(selector)”) ‘whether or not it contains an Element, such as $(“p:has(span)”) represents all p elements that contain span elements $(“Element:hidden”) ‘selects all visible elements $(“Element:visible”) ‘selects all invisible elements

6. Other object acquisition methods $(“Element[id]”) ‘all elements with an id attribute $(“Element[attribute = youlika]” ‘gets all the elements with an attribute of youlika $(“Element[attribute!= youlika]” ‘gets all the elements whose attribute is not youlika $(“Element[attribute ^= youlika]” ‘gets all elements whose attribute is not the beginning of youlika $(“Element[attribute $= youlika]” ‘gets all elements whose attribute is not the end of youlika $(“Element[attribute *= youlika]” ‘gets all the elements for which an attribute contains the beginning of youlika $(” Element [selector1] [selector2] […]. ”) ‘matches the attribute selector, such as $(“input[id][name][value=youlika]”) to get the input element with the id, name, and value being youlika.

7. Acquisition of child elements $(“Element:nth-child(index)”) ‘selects the NTH Element below the parent level $(“Element:nth-child(even)”) ‘selects the even number below the parent level $(“Element:nth-child(odd)”) ‘selects the odd number below the parent level $(“Element: NTH -child(3n+1)”) ‘expression $(“Element:first-child”) ‘selects the first child under the parent $(“Element:last-child”) ‘selects the last child below the parent $(“Element: sole-child ”) ‘matches a unique child of the parent, for example, dt is unique in the dl list, then dt is selected

8. Form object acquisition $(:input)// finds all input elements, as well as drop-down lists, text fields, checkboxes, and so on. $(:text)// matches all single-line text boxes $(:password)// matches all password fields $(:radio)// matches all radio buttons $(:checkbox)// matches all check boxes $(:submit)// matches all submit buttons $(:image)// matches all image fields, for example $(:reset)// matches all reset buttons $(:button)// matches all the buttons $(:file)// matches all file upload fields $(:hidden)// matches all invisible elements or elements of type hidden $(:enabled)// matches all available input elements, such as radio:enabled, which matches all available radio buttons $(:disabled)// matches all the unavailable input elements $(:checked)// matches all checked box elements $(:selected)// matches all drop-down lists

9. Set and remove element attributes $(” Element ”). Attr (name) ‘in the first match of attribute values, such as $(” img ”). Attr (” SRC ”) $(“Element”.attr(key,value)”) ‘sets an attribute for an Element $(” Element ”. Attr ({key: value, key1: value,… })) ‘set multiple attributes for an element at once $(“Element”).attr(key,function) ‘sets a computed attribute value for all matched elements. $(“Element”). RemoveAttr (name)// removes an attribute