Summary of usage of setInterval in JavaScript_javascript skills

The setInterval action is used to call functions, methods or objects at certain intervals when playing animation. You can use this action to update variables from the database or update the time display.

The syntax format of the setInterval action is as follows:
setInterval(function,interval[,arg1,arg2,...argn])
setInterval(object,methodName ,interval[,arg1,arg2,...argn])

The first format is the default syntax for the setInterval function in the standard action panel, and the second format is the method used in expert mode actions.

The parameter function is a function name or a reference to an anonymous function. The object parameter specifies an object derived from the Object object. methodName specifies the method to be called in the object parameter.

interval specifies the time between two calls to function or methodName, in milliseconds. The following arg1 and so on are optional parameters, used to specify the parameters passed to function or methodName.

setInterval The time interval it sets is less than the animation frame rate (such as 10 frames per second, equivalent to 100 milliseconds), then the function is called at a time interval as close as possible to the interval.

And the updateAfterEvent action must be used to ensure that the screen is refreshed with sufficient frequency. If interval is greater than the animation frame rate, it is only called every time the playhead enters a certain frame to reduce the impact of each screen refresh.

The following example calls an anonymous function every 1 second.
setInterval(function(){trace("I will display it every 1 second")},1000);//The function(){} here is a function without a function name. Become an anonymous function, the following 1000 is the time interval, the unit is milliseconds.

The following example shows us how to run it with parameters.

Copy code The code is as follows:

function show1(){
trace("Every Displayed every 1 second");
}
function show2(str){
trace(str);
}
setInterval(show1,1000);
setInterval(show2, 2000,"I will display it every 2 seconds");

The setInterval method of the function has been introduced above.

Below we will introduce the setInterval method of the object.

First, write an example of calling the setInterval method of an object in an action. This example does not require passing parameters.

Copy code The code is as follows:

myobj=new Object();//Create a new Object
myobj.interval=function){
trace("Displayed every 1 second");
}//Method to create an object.
setInterval(myobj,"interval",1000);//Set the time interval to call the object's method.

Next, we will introduce how to pass parameters. In fact, the principle is the same as passing parameters of functions.

Copy code The code is as follows:

myobj=new Object();
myobj. interval-function(str){
trace(str);
}
setInterval(myobj,"interval",2000,"I will display it every 2 seconds");

Attention. When you want to call methods defined for an object, you must use the second syntax format in expert mode.

In this case, let’s make a screen that dynamically displays the time. This can be achieved with the following code.

Copy code The code is as follows:

setInterval(show,1000);
function show (){
time=new Date();
hour=time.getHours();
minu=time.getMinutes();
sec=time.get.Seconds();
datetime=hour ":" minu ":" sec;
}//The datetime here is the variable name of a dynamic text box.

Looking like this, everyone should have learned the setInterval method very well. Now, let’s learn clearInterval.

The role of the clearInterval action is to clear the call to the setInterval function. Its syntax format is as follows: clearInterval(intervalid); intervalid is the object returned after calling the setInterval function.

Here’s a simple example.

Copy code The code is as follows:

function show(){
trace("Every Displayed once every second");
}
var sh;
sh=setInterval(show,1000);
clearInterval(sh);