Javascript的setInterval和setTimeout方法

setInterval方法

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 include the parentheses.

window.setInterval(someFunction, 5000);

setTimeout 方法

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Evaluates an expression after a specified number of milliseconds has elapsed.

Syntax

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

Parameters

vCode	Required. Variant that specifies the 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 one of the following values: JScript Language is JScript. VBScript Language is VBScript. JavaScript Language is JavaScript.

Return Value

Integer. Returns an identifier that cancels the evaluation with the clearTimeout method.

Remarks

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

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

The specified expression or function is evaluated once . For repeated evaluation, use the setInterval method.