Simple ArmA2 OA Keygen [HTML]

<!DOCTYPE html>
<html>
<style>
textarea {
width:375px;
height:500px;
resize:none;
}
</style>
<body>
<h1>Arma 2 OA Key Generator - Made by Shad0w</h1>
<h3>Generate random keys: <button onclick="randomKeys()">Generate</button> <button onclick="clearKeys()">Clear</button></h3>
<button onclick="selectAll()">Select All</button><br>
<textarea id="random_keys" readonly></textarea>
<script>
function randomKeys() {
var keys = prompt('How many keys would you like to generate? \n\nNote* - gets slow if generating 2000+. Typically if it stops responding, just wait and it will finish generating.');
var n = 0;
while(n < Number(keys)){
    var char1 = "048C";
    var char2 = "0246";
    var chars = "0123456789ABCDEF";
	var string_length = 28;
    var random1 = '';
    var random2 = '';
	var randomstring = '';
	for (var i=0; i<string_length; i++) {
		var rnum = Math.floor(Math.random() * chars.length);
			randomstring += chars.substring(rnum,rnum+1);
	}
        var rnum1 = Math.floor(Math.random() * char1.length);
			random1 += char1.substring(rnum1,rnum1+1);
        var rnum2 = Math.floor(Math.random() * char2.length);
			random2 += char2.substring(rnum2,rnum2+1);

	document.getElementById('random_keys').innerHTML += random1+''+random2+''+	randomstring+'\n';
	n++;
	}
}
function clearKeys() {
	document.getElementById('random_keys').innerHTML = '';
}
function selectAll(){
	document.getElementById("random_keys").select();
}
</script>
</body>
</html>