js定时器

JavaScript timer is a time-based event control technology that can execute a specified task according to the designated time or time period. It is widely used in web front-end development and many web pages.
JavaScript timer is an indispensable part of JavaScript and is a powerful weapon that many small web pages must use. It is the basis for implementing various interactive effects on webpages. There are generally three ways to implement a timer in JavaScript, namely setTimeout(), setInterval() and setImmediate(). Timer works can help us better control page effecs.
The setTimeout() timer is used to delay the execution of a JavaScript function once. The average setTimeout() interval we set is usually between zero milliseconds and two seconds, if greater than two seconds, we usually call setInterval().
The setInterval() timer is used to continuously execute the JavaScript function until it is cleared. The setInterval () timer calls the function at a specified time period, so it can execute multiple times. It works like a record, which is convenient when some processing needs to be done repeatedly.
The setImmediate() timer can trigger a callback immediately after JavaScript callbacks are unloaded or after the current task runs. You can execute asynchronous JavaScript code at the right time.
In short, the JavaScript timer is a basic tool that helps realize different task routines of webpages. It implements the time period control functions of tasks very well and has been used in many fields of webpages.