<script language="JavaScript">
function person_in() {enter=new Date();}
function person_out() {exit=new Date();
time_dif=(exit.getTime()-enter.getTime())/1000;
time_dif=Math.round(time_dif);
alert ("You've only been here for: " + time_dif + " seconds!")}
startday = new Date();
clockStart = startday.getTime();
function initStopwatch()
{var myTime = new Date();
var timeNow = myTime.getTime();
var timeDiff = timeNow - clockStart;
this.diffSecs = timeDiff/1000;
return(this.diffSecs);}
function getSecs()
{var mySecs = initStopwatch();
var mySecs1 = ""+mySecs;
mySecs1= mySecs1.substring(0,mySecs1.indexOf(".")) + " сек";
document.forms[0].timespent.value = mySecs1
window.setTimeout('getSecs()',1000); }
</script>

<Form>
Ваше время на этой странице:
<Input Type="Text" Size="9" Name="timespent">
</Form>