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This article mainly talks about "what are the methods of JavaScript cycle". Interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn "what are the methods of JavaScript cycle?"

Js's three loop methods: 1, while loop, syntax "while (conditional expression) {statement block}"; 2, "do-while" loop, syntax "do {statement block} while (conditional expression)"; 3, for loop, syntax "for (variable initialization; conditional expression; variable update) {statement block}".

The operating environment of this tutorial: windows7 system, javascript1.8.5 version, Dell G3 computer.

When using JavaScript, we often encounter the need to run the same code over and over again, and this is not a waste of time, but also inefficient, the use of loops is a wise choice, greatly improve efficiency, but also reduce the amount of code.

There are three types of loops in JS:

1. While cycle

2. Do-while cycle

3. For cycle

I. while cycle

1. The grammatical structure of while loop:

While (conditional expression) {the block of statements to be executed when the conditional expression is a Boolean true

2. The application of while cycle.

While loops are often used in situations where you don't know the number of loops, such as letting the user loop into an integer until you enter a particular character, and you can't wait until the number of times the loop will occur. For example:

Second, do... While

1. Do... The syntax structure of while:

Do {statement block executed when the conditional expression is true} while (conditional expression)

2. Do... Application of while

Do-while differs from a while loop in that it executes the statement in the loop, then determines whether the expression is true, continues the loop if it is true, and terminates the loop if it is false. Therefore, the do-while loop must execute the loop statement at least once. As follows:

III. For cycle

1. The grammatical structure of for loop:

For (variable initialization; conditional expression; variable update) {execute statement block when conditional expression is true

2. The application of for cycle.

The for loop is often used in cases where the number of loops is relatively clear, that is, you can see at a glance that you need to loop several times, and it is more intuitive. The first sentence of the for loop contains the conditions for initializing the end of the loop and the value of each update, and the loop body does what you really want to do. For example, for (nasty 1)

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