Takes a textarea/input and deletes the text bit by bit

simulate_delete

function clear(el) {
	var interval = 300;
	var charactersToRemove = 1;
	var id = setInterval(function(ev) {
		var x = $(el).val();
		if(!x) {
			clearInterval(id);
		} else {
			var pos = x.length - charactersToRemove;
			x = x.substr(0, pos);
			$(el).val(x);
			charactersToRemove *= 2
		}
	}, interval);
}