Hi,
First of all, it is not recommended to perform button click from script however, we can call the embedded function with certain time duration.
<html>
<head>
<script>
function buttonClick()
{
document.getElementById("output").innerHTML += "Clicked! ";
setTimeout(function(){
buttonClick()
}, 1000);
}
</script>
</head>
<body>
<button onclick="buttonClick()">Click Me </button>
</body>
</html>
for your scenario the time duration should be 7200000.
Thanks