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The SetInterval () method invokes a function or evaluates an expression according to the specified period (in milliseconds).
The SetInterval () method keeps calling functions until Clearinterval () is called or the window is closed. The ID value returned by SetInterval () can be used as a parameter to the Clearinterval () method.
GrammarSetInterval (code,millisec[, "Lang"])
| Parameters | Description |
|---|---|
| Code | Necessary. The function to invoke or the code string to execute. |
| Millisec | Have to. The time interval, in milliseconds, between periodically executing or calling code. |
A value that can be passed to Window.clearinterval () to suppress periodic execution of code.
Example:
<body>
<form>
<input type= "text" id= "clock" size= "/>"
<script language=javascript>
var int=self.setInterval("clock()", 50)
function Clock () {
var t=new Date ()
document.getelementbyidx_x_x_x_x_x ("Clock"). Value = t
}
</script>
</form>
<button onclick= "int= window.clearInterval(int)"> Stop interval</button>
</body>
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Cleartimeout () and Clearinterval ():
JS Set delay:
Using setinterval and setting the delay function settimeout very similar.
SetTimeout used to delay a period of time before doing an operation.
SetTimeout ("function", time) sets a timeout object
SetInterval ("function", time) //Set a timeout object
SetInterval for automatic repetition, settimeout does not repeat.
Cleartimeout (object) clears the SetTimeout object that has been set
Clearinterval (object) clears the SetInterval object that has been set
first, what is called Javas timing Events for Cript
Using JavaScript can implement deferred execution of code, which means that when a function is called, it does not execute some code immediately, but waits for a specified amount of time to execute, which is called a timing event.
Second, Javas cript function of the timing event
SetTimeout () //-execute code after a specified time
Cleartimeout () //-cancel SetTimeout ()
Note: setTimeout () and cleartimeout () are functions of the Window object of the HTML DOM.
Three, settimeout detailed
var t = setTimeout ("javascript statement", time parameter)
Note: The time parameter unit is milliseconds
Example: Var t=settimeout ("Alert (' 3 seconds! ')", 3000)
If the JS statement has a variable, you must concatenate the variable with the + sign, such as:
var t = setTimeout ("document.getelementbyidx_x_x_x_x_x" ("+menuid+"). style.display= ' None ' ", 3000)
Four, Cleartimeout detailed
Syntax: cleartimeout (variable name for settimeout)
Example: Cleartimeout (t) //where T is the variable of the settimeout set above
Use Cleartimeout to stop timing at any time.
V. Application Skills
It is recommended that settimeout be set individually as a function. Such as:
function Delayrun (code, time) {
var t = setTimeout (code, time);
}
This way, when you need to delay execution of a piece of code, simply add the function before the code. Such as:
onmouseover = Delayrun ("Settab (0,0)", 500)
Where Settab is a custom function. If you do not want to let settab delay execution later, then remove the Delayrun-related code in the statement,
Change to: Onmouseover=settab (0, 0) on it.
This kind of writing avoids each need to delay the place to write a piece of settimeout code, just need to call directly can, very convenient. It also saves the amount of code.
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Self-made table: used to display the current time of the
<! DOCTYPE html>
<body>
<p>a script on the page starts this clock:</p>
<p id= "Demo" ></p>
<script>
var myvar=setinterval (function () {MyTimer ()},1000);
function MyTimer ()
{
var d=new Date ();
var t=d.tolocaletimestring ();
document.getElementById ("Demo"). Innerhtml=t;
}
</script>
</body>
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