Adding Time Per Button Click

I am new to javascript (4 months), I would like to add an hour to the current time each time a button is clicked.

I have this code:
var hourstbutton=document.getElementById("button3");
hoursbutton.onclick=function() {
var divlink=document.getElementById("math3");
var newtime2=new Date();
var currenthours2=newtime2.getHours()+1;
var currentmins2=newtime2.getMinutes();
var currentsecns2=newtime2.getSeconds();
var ampm2= (currenthours2>=12) ? "P.M." : "A.M.";
if (currenthours2>=13) {
currenthours2-=12;
}if(currenthours2<1){
currenthours2=12;
}if(currentmins2<10){
currentmins2= "0" + currentmins2;
}if(currentsecns2<10){
currentsecns2="0" + currentsecns2;
}
divlink.innerHTML=currenthours2+":"+currentmins2+":"+currentsecns2+ " "+ampm2;

How do I tie the number of button clicks into the number of times this code is executed?