What are the timers in javascript

There are two types of timers in JavaScript: 1. Single timer, defined using the setTimeout() method, which can execute a code block once after the specified time (in milliseconds); 2. Loop timer, Use the setInterval() method to define certain codes to be executed repeatedly according to a specified period (in milliseconds).

The operating environment of this tutorial: windows7 system, javascript version 1.8.5, Dell G3 computer.

In JavaScript, we can use timers to delay the execution of certain codes, or to repeatedly execute certain codes at fixed intervals. For example, you can use a timer to regularly update the ads on the page or display a real-time clock, etc.

JavaScript provides two timers: setTimeout() and setInterval()

setTimeout()

JS setTimeout() function is used to execute certain code after the specified time. The code is only executed once.

Usage:

setTimeout(code,millisec)

• code Required. The string of JavaScript code to be executed after the function to be called.

• #millisec Required. The number of milliseconds to wait before executing code.

Example:

   
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setInterval()

JS setInterval() function can define a timer that can be executed repeatedly , each execution needs to wait for the specified time interval.

Usage:

setInterval(code,millisec[,"lang"])

• code Required. A function to be called or a string of code to be executed.

• #millisec Required. The time interval, in milliseconds, between periodic executions or calls to code.

Example:

   
  获取验证码    

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