Javascript timing events
 
With Javascript you can execute functions or statements not immediately but after a specified time interval. The two methods (of the HTML DOM Window object) are:
 
  • setTimeout() - execute a code some time in the future
  • clearTimeout() - cancel the setTimeout()
 

setTimeout()

Sintax:
var t=setTimeout(function, delay*)
*(in milliseconds: 2 seconds = 2 * 1000)

setTimeout() returns a value we have stored in the 't' variable. You can refer to this value if you want to cancel the setTimeout().

The first parameter is a string containing a Javascript statement or function.

The second parameter specifies how many milliseconds you want to delay the your function or statement.

The example below shows a message after a 5 seconds delay
var t=setTimeoout("alert('5 seconds')",5000);

clearTimeout()
 
Sintax:
clearTimeout(setTimeout_variable)
example:
<html>
<head>
<script type="text/javascript">
var t

function time(){
    setTimeout("alert()",5000);
}

function stoptime(){
    clearTimeout(t);
}
</script>
</head>
<form>
<input type="button" value="count" onClick="time()"><br>
<input type="button" value="stop" onClick="stoptime()">
</form>
</html>
This example shows the two timing functions: the first button starts a 5 second delay before an alert message and the second one stops this counter cleaning the operation.
Last Updated ( giovedì, 29 novembre 2007 )