window.setInterval()
var timer = window.setInterval(
yourTimerHandler,
delay
);
an example
var timer = window.setInterval(
function(){
var objFSO=new ActiveXObject("Scripting.FileSystemObject");
var objStream=objFSO.OpenTextFile("c:\test.txt",ForReading,true,false);
objStream.Close();
},
3000 /* 3 seconds */
);