1 option a--by name
$('tag') Example: $('a') selects all tags
$('#id name') Example: $('#a1') selects the tag whose id is equal to a1 $('#a1: attribute value ddd') selects all tags whose id is equal to a1 and contains the ''attribute value ddd""
$('.classname') Example: $('.a1') selects all tags whose class name is a1: $('div.a1') selects tags whose type is div and whose class name is equal to a1
Example: $('.a1 div') selects all hierarchical div tags included under the a1 tag with all class names
Example: $('.a1>div') selects all first-level sub-div tags contained under the a1 tag with all class names
Example: $('.a1.b1') selects all tags with class name a1 and b1
Example: $('.a1,b1') selects all tags with class name a1 or b1
$([attribute name=attribute value]) and $([attribute name=attribute value])
Example: $('[for]') selects all tags whose attribute names contain for
Example: $("[type='text']"') selects all tags whose attribute name is type and whose value is text
Example: $(':text') The form type is an input tag, which can be directly abbreviated as an input tag whose attribute value is text
2 option b-pass filter
$(this).next() The next label of the current selection set, you can set conditions for precise filtering
$(this).prev() The previous label of the current selection set, you can set conditions for precise filtering
$(this).parent() The parent tag of the current selection set, you can set conditions for precise filtering
$(this).childern() The child tag of the current selection set, you can set the condition for precise filtering
$(this).siblings() The sibling tag of the current selection set, you can set the condition for precise filtering
3 Selection method c - Chain selection by filter
$(this).next(condition
).parent(condition).siblings(condition).first() Get the first of the set of sibling tags of the next parent tag of the current tag
4 Choice method d - miscellaneous choices
$(this).eq(1) Take the 2nd of the current tag set
$(this).last() takes the last one of the current tag set
$(this).find(condition) Get the qualified tags of the current tag set