Base64 Decoder

<script>
	function decode() {
		var input = document.getElementById('input').value;
		var output = document.getElementById('output');
		var padding = '';
		if (input.length % 4 !== 0) {
			var padCount = 4 - input.length % 4;
			padding = Array(padCount + 1).join('=');
		}
		var decoded = atob(atob(input + padding));
		output.value = decoded;
	}
</script>