window.onload = showTheTime;

function showTheTime() {
var now = new Date();

var theTime = showTheHours(now.getHours()) + showZeroFilled(now.getMinutes()) + showZeroFilled(now.getSeconds()) + showAmPm();
document.getElementById("showTime").innerHTML = theTime;
setTimeout("showTheTime()" ,1000);

function showTheHours(theHour) {
if (theHour == 0) {
return 12;
}
if (theHour < 13) {
return theHour;
}
return theHour-12;
}

function showZeroFilled(inValue) {
if (inValue > 9) {
return ":" + inValue;
}
return ":0" + invalue;
}

function showAmPm() {
if (now.getHours() < 12) {
return " am";
}
return " pm";
}
}