javascript map foreach

,arrayy) {...})But for NodeList to use the following notation.[].foreach.call (Lists,function (Valule.index.arrayy) {...})Why can ' t I use ForEach or map on a NodeList?NodeList is used very much like arrays and it would is tempting to use array.prototype methods on them. This is, however, impossible.JavaScript has a inheritance mechanism based on prototypes. Array instances inherit array methods (such as

foreach is a method of manipulating an array in ES5, and the main function is to iterate through the array, for example:var arr = [1,2,3,4];arr.foreach (alert); equivalent to:var arr = [1, 2, 3, 4]; for (var k = 0, length = arr.length; k ) {alert (array[k]);}The function callback in the Foreach method has three parameters: the first argument is the array contents of the traversal, the second parameter is t

foreach is a method of manipulating an array in ES5, and the main function is to iterate through the array, for example:1 var arr = [1,2,3,4]; 2 Arr.foreach (alert);Equivalent to:1 var arr = [1, 2, 3, 4]; 2 for (var k = 0, length = arr.length; k ) {3 alert (array[k]); 4 }The function callback in the Foreach method has three parameters: the first argument is the array contents of the traversal, the second

foreach is a method of manipulating an array in ES5, and the main function is to iterate through the array, for example:　　 12 vararr = [1,2,3,4];arr.forEach(alert); Equivalent to: 1234 vararr = [1, 2, 3, 4];for(vark = 0, length = arr.length; k alert(array[k]);} The function callback in the Foreach method has three parameters: the first argument

Copy code code as follows: var ForEach = (function () { Traversal of arrays and pseudo arrays var _array_foreach = function (Array, block, context) { if (array = = null) return; Special handling of String if (typeof array = = ' string ') { Array = Array.split ('); } var i = 0,length = Array.Length; for (; i }; Traversal of objects var _function_foreach = Function (object, block, context) { for (var key in object) {

foreach is a method of manipulating an array in ES5, and the main function is to iterate through the array, for example:　　var arr = [1,2,3,4];arr.foreach (alert);Equivalent to:var arr = [1, 2, 3, 4];for (var k = 0, length = arr.length; k The function callback in the Foreach method has three parameters: the first argument is the array contents of the traversal, the second parameter is the corresponding array

JavaScript has been born for more than 20 years. The method we have been using to loop an array is as follows:For (var index = 0; index Console. log (myArray [index]);}Since JavaScript5, we can use the built-in forEach method:MyArray. forEach (function (value ){Console. log (value );});It is a lot easier to write, but it also has a short note: you cannot interrup

(unordered), The first two parameters that come in are element value function (now_element,now_elem,thisset) { //The third parameter is the same every iteration, output only once look at it. if (control=== False) { control=true; Console.log ("This set is" +thisset); Console.log (the type of the 3rd argument is "+typeof thisset"); } Console.log ("1th parameter =" +now_element); Console.log ("2nd parameter =" +now_ele

1. js Array loop traversal.Array loop variables, the first thing to think about is the for (Var i=0;iIn addition, a simpler foreach method can be used2. The ForEach function.Both Firefox and Chrome's array types have a foreach function. Use the following:[HTML]View Plaincopy > HTML> HEAD> title> New Document title> META name= "Author" content

JavaScript is a literal translation script language, a dynamic type, a weak type, a prototype based language, and a built-in support type. Its interpreter, known as the JavaScript engine, is widely used as a scripting language for clients, and is used in HTML (an application under standard Universal Markup Language) to add dynamic functionality to HTML Web pages. JavaS