Day27-javascript Realization Timer and its application case

Career development, code 100 days--2018-04-12

There are two types of timers in JavaScript, namely SetInterval and settimeout, which are used as follows:

Open:

SetTimeout ("function", time) sets a timeout object, delays execution, and executes only once

SetInterval ("function", time) sets a timeout object; continuous execution; repeated execution

* Both of the above methods have a return value, i.e. the timer object is changed. The object can be entered as a closed object.

Shut down:

Cleartimeout (object) clears the SetTimeout object that has been set
Clearinterval (object) clears the SetInterval object that has been set

such as the opening and closing of a Window object

var timer = window.setinterval (express,millseconds);

Window.clearinterval (timer);

var timer = window.settimeout (express,millseconds);
Window.cleartimeout (timer);

Timer Start-Stop use case:

Set two buttons to control the opening and closing of the timer, respectively

<type= "button"  name= "Start"  ID= "BTN1"  Value= "Start"><type= "button"  Name= "Stop"  ID= "BTN2"  value= "Stop">

JavaScript implements timer start-stop control

<script type= "Text/javascript" >//Timer Usage        //var timer = window.setinterval (express,millseconds); Window.clearinterval (timer);        //var timer = window.settimeout (express,millseconds);        //window.cleartimeout (timer);Window.onload =function () {            varBTN1 = document.getElementById ("BTN1"); varBTN2 = document.getElementById ("btn2"); varTimer =NULL; Btn1.onclick=function() {Timer=setinterval (function() {alert ("Hello"); },1000);            }; Btn2.onclick=function() {clearinterval (timer);                    }; }    </script>

Click "Start" button, every second pop-up box "Hello", that is, the timer turn on; Click "Stop" button, the prompt box no longer pops up, that is, the timer is off.

Day27-javascript Realization Timer and its application case