JavaScript Loops

Last Updated Jul 29, 2015, 07:00:14 PM




JavaScript Loops

Loops are used to perform repeatable tasks in programming without writing the same logic for each iteration. JavaScript has different types of loops which are used to perform various tasks. Let us look at each javascript loop with examples

The while loop is used to exectue a specific statement as long as the test condition evolutes to true . The condition is evaluated before executing the statement.

Syntax

Values

condition

The test condition to evaluate the execution of the statement.

statement

The key statement to execute until the condition becomes true

Example

Each iteration, the loop increments n and adds it to m. Therefore, m and n take on the following values:

After the first pass: n = 1 and m = 1

After the second pass: n = 2 and m = 3

After the third pass: n = 3 and m = 6

After the third pass: n = 4 and m = 12

After completing the third pass, the condition n < 10 is no longer true, so the loop terminates.

Another JavaSript While loop Example



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JavaScript do while loop

The do...while statement executes the loop statement until the condition becomes false. The do while loop must execute each statement at least once.

Syntax
statement

A statement that is executed at least once

condition

The test condition to evaluate the execution of the statement.


Example

In the above example, the do...while loop iterates at least once and reiterates until x is no longer less than 10.



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JavaSript For Loop

The for statement allow the code to be executed repeatedly . For loops are often used to iterate over a list of itemes


Syntax
initialization

Initial expression to start the loop execution, typically a counter value or variable.

condition

The test condition to specify when to terminate the loop or how long does the loop should run.

final-expression

Final expression typically, ends the iteration each time by incrementing or decrementing the initial value

statement

The key statement to execute the loop until a specific condition becomes true.


Example

In the above example, the variable n initialized with 0, it checks if the variable n is less than 9 then it will print that variable while the value of n will keep increased until the condition becomes false


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JavaScript Break Statement

The break statement terminates the current loop, switch, or label statement and transfers program control to the statement following the terminated statement.

The break statement includes an optional label that allows the program to break out of a labeled statement.

Syntax
Example
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JavaScript Continue Statement

The continue statement terminates execution of the statements in the current iteration of the current or labeled loop, and continues execution of the loop with the next iteration


Syntax

The continue statement can include an optional label that allows the program to jump to the next iteration of a labeled loop statement instead of the current loop. In this case, the continue statement needs to be nested within this labeled statement.


Example
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Practice with our Interactive Editor and take your JavaScript Skills to the next level
Exercise 1 Exercise 2 Exercise 3 Exercise 4 Exercise 5 Exercise 6


Browser compatibility
Feature
Basic support Yes Yes Yes Yes Yes Yes Yes




Sources and Credits

The source of the content has been referred and updated with Mozilla Developer Network and W3C Organization

Last Updated Jul 29, 2015, 07:00:14 PM





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