setInterval Method

Evaluates an expression each time a specified number of milliseconds has elapsed.

Syntax

iTimerID = window.setInterval(vCode, iMilliSeconds [, sLanguage])

Parameters

vCode	Required. Variant that specifies a function pointer or string that indicates the code to be executed when the specified interval has elapsed.
iMilliSeconds	Required. Integer that specifies the number of milliseconds.
sLanguage	Optional. String that specifies any one of the possible values for the LANGUAGE attribute.

Return Value

Integer. Returns an identifier that cancels the timer with the clearInterval method.

Remarks

The setInterval method continuously evaluates the specified expression until the timer is removed with the clearInterval method.

In versions earlier than Microsoft® Internet Explorer 5, the first argument of setInterval must be a string. Evaluation of the string is deferred until the specified interval elapses.

As of Internet Explorer 5, the first argument of setInterval can be passed as a string or as a function pointer.

To pass a function as a string, be sure to suffix the function name with parentheses.

window.setInterval("someFunction()", 5000);

When passing a function pointer, do not to include the parentheses.

window.setInterval(someFunction, 5000);

Include the parentheses to have the function evaluated immediately before setInterval is called. The result of the function is passed to setInterval rather than to the function.

To retrieve a function pointer, use the code shown in the following example:

function callback()
{
    alert("callback");
}

function callback2()
{
    alert("callback2");
}

function chooseCallback(iChoice)
{
    switch (iChoice)
    {
    case 0:
        return callback;
    case 1:
        return callback2;
    default:
        return "";
    }	
}

// if i is 0, callback is invoked after 5 seconds
// if i is 1, callback2 is invoked
// otherwise, the timer is not set
window.setInterval(chooseCallback(i), 5000);

Example

Sample Code

This example uses the setInterval method to create a DHTML clock. A variable is assigned to the interval, and can be used as a reference to stop the interval using the clearInterval method.

var oInterval = "";

function fnStartInterval(){
   oInterval = window.setInterval("fnRecycle()",1000);
}
function fnRecycle(){
   // Code to display hours, minutes, and seconds.
}

This feature requires Microsoft® Internet Explorer 4 or later. Click the icon below to install the latest version. Then reload this page to view the sample.

Applies To

[ Object Name ] Platform Version Win16: Win32: Mac: Unix: WinCE: Version data is listed when the mouse hovers over a link, or the link has focus.	window

See Also

clearInterval, setTimeout

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