How to Use traversal functions in jQuery

Measure the test taker's knowledge about how to use traversal in jquery. The jQuery traversal function includes methods for filtering, searching, and concatenating elements.

Function Description

. Add () adds the element to the set of matching elements.

. AndSelf () adds the previous element set in the stack to the current set.

. Children () obtains all child elements matching each element in the element set.

. Closest () matches the parent element step by step from the element itself and returns the first matched ancestor element.

. Contents () obtains the child elements of each element in the matched element set, including text and comment nodes.

. Each () iterates on jQuery objects and executes functions for each matching element.

. End () ends the last filtering operation in the current chain and returns the Matching Element Set to the previous status.

. Eq () reduces the set of matching elements to the new element located in the specified index.

. Filter () reduces the set of matching elements to the new elements returned by the matching selector or matching function.

. Find () gets the descendant of each element in the current matched element set, which is filtered by the selector.

. First () reduces the set of matching elements to the first element in the set.

. Has () reduces the set of matching elements to the set of descendants containing specific elements.

. Is () checks the current Matching Element Set Based on the selector. if at least one matching element exists, true is returned.

. Last () reduces the set of matching elements to the last element in the set.

. Map () transmits each element in the current matching set to the function to generate a new jQuery object containing the returned value.

. Next () gets the peer element that matches each element in the element set.

. NextAll () obtains all peer elements after each element in the matched element set, which are filtered by selector (optional ).

. NextUntil () obtains all peer elements after each element until an element matching the selector is met.

. Not () deletes an element from the matched element set.

. OffsetParent () gets the first parent Element Used for positioning.

. Parent () gets the parent element of each element in the current matched element set, which is filtered by the selector (optional ).

. Parents () gets the ancestor elements of each element in the currently matched element set, which are filtered by selector (optional ).

. ParentsUntil () obtains the ancestor element of each element in the current matched element set until an element that matches the selector is encountered.

. Prev () is used to obtain the first peer element next to each element in the matched element set, which is filtered by the selector (optional ).

. PrevAll () is used to obtain all the peer elements before each element in the element set. The selector filters (optional ).

. PrevUntil () obtains all peer elements before each element until an element matching the selector is met.

. Siblings () is used to obtain the peer elements of all elements in the matched element set, which are filtered by selector (optional ).

. Slice () reduces the set of matching elements to a subset of the specified range.

Each usage

1. each in the array

Var arr = ["one", "two", "three", "four"]; $. each (arr, function () {alert (this) ;}); // The above each Outputs one, two, three, four var arr1 = [[1, 4, 3], [4, 6, 6], [7, 20, 9] $. each (arr1, function (I, item) {alert (item [0]) ;}); // In fact, arr1 is a two-dimensional array, and item is equivalent to taking every one-dimensional array, // item [0] is relative to the first value in each one-dimensional array. // The above each output is: 1 4 7 var obj = {one: 1, two: 2, three: 3, four: 4}; $. each (obj, function (I) {alert (obj [I]) ;}); // This each is more powerful and can loop through every attribute. // The output result is: 1 2 3 4

2. Traverse Dom elements