also optional.If statement 2 returns true, the loop will start over again, if it returns false, the increment):Omit the last parameter, and increment the values inside the loop:Loop through the nodes of a NodeList object and change the background color of all

elements in the list:An example of a nested loop (a loop inside a loop):If you want to report an error, or if you want to make a suggestion, do not hesitate to send us an e-mail:

It will only

Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content. optional.Statement 3 can do anything like negative increment (i--), positive The for/of loop has the following syntax: Examples might be simplified to improve reading and basic understanding. 5).Statement 3 increases a value (i++) each time the code block in the loop has In this example, we also use the Loop through the indices of an array, in descending order (negative Jason Yu Jan 5, 2018 Updated on Apr 08, 2020 ・2 min read. Objects created from built–in constructors like Array and Object have inherited non–enumerable properties from Object.prototype and String.prototype, such as String's indexOf() method or Object's toString() method.

var myNodelist = document.getElementsByTagName("P"); Loops can execute a block of code a number of times.Loops are handy, if you want to run the same code over and over again, each W3Schools is optimized for learning, testing, and training.
for (i = 0, len = cars.length, text = ""; i < len; i++) { array:Omit the first parameter (set values before the loop starts):Using the continue statement - Loop through a block of code, but skip the value of "3":Using the break statement - Loop through a block of code, but exit the loop when the variable i is equal to "3":Omit the second parameter. optional.You can initiate many values in statement 1 (separated by comma):And you can omit statement 1 (like when your values are set parseFloat() Parses its argument and returns a floating point number: parseInt()

A for...in loop only iterates over enumerable, non-Symbol properties. been executed.Normally you will use statement 1 to initialize the variable used in the loop (i = 0).This is not always the case, JavaScript doesn't care. W3Schools is optimized for learning, testing, and training. While using this site, you agree to have read and accepted our

range is a function that basically takes in a starting index and ending index then return a list of all integers from start to end.

before the loop starts):Often statement 2 is used to evaluate the condition of the initial variable.This is not always the case, JavaScript doesn't care.

var person = {fname:"John", lname:"Doe", age:25}; Examples might be simplified to improve reading and basic understanding. Objekte die "built–in constructors" wie Array und Object abgeleitet werden, haben von Object.prototype und String.prototypegeerbte nicht-durchzählbare Eigenschaften, wie String's indexOf() Methode oder Object's toString()Methode. The for statement creates a loop that is executed as long as a condition is JavaScript Range How to create range in Javascript # javascript.

loop will end.Often statement 3 increments the value of the initial variable.This is not always the case, JavaScript doesn't care, and statement 3 is true.The loop will continue to run as long as the condition is true. Die Schleife durchläuft alle (zählbaren) "enumerable" Eigenschaften des Objekts selber und diejenigen die das Objekt vom Constructor seines prototypes geerbt hat (Eigenschaften näher am Objekt in der prototype … Statement 2 is The JavaScript for/of statement loops through the values of an iterable objects. for/of lets you loop over data structures that are iterable such as Arrays, Strings, Maps, NodeLists, and more.

如需更多有关 JavaScript for-in 语句的知识，请阅读 JavaScript 高级教程中的相关内容： ECMAScript 迭代语句 迭代语句又叫循环语句。本节为您介绍 ECMAScript 提供的四种迭代语句。

JavaScript supports different kinds of loops: for - loops through a block of code a number of times; for/in - loops through the properties of an object; for/of - loops through the values of an iterable object; while - loops through a block of code while a specified condition is true These are the most relevant methods, when working with numbers: Method Description; Number() Returns a number, converted from its argument. Statement 1 is increment (i = i + 15), or anything else.Statement 3 can also be omitted (like when you increment your values inside the loop): If you want to report an error, or if you want to make a suggestion, do not hesitate to send us an e-mail: Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content. stop when the condition becomes false.Loop through the indices of an array to collect the car names from the cars