たまに生で code block 書くときにめんどかった。TAB で移動はつかわないし

	$X("//textarea").forEach(function (t) {
		t.addEventListener("keypress", function (e) {
			if (e.keyCode == 9) {
				e.stopPropagation();
				e.preventDefault();
				var s = t.selectionStart;
				var content = t.value;
				var str = "\t";
				var newstr = content.substring(0, s) + str + content.substring(s, content.length);
				t.value = newstr;
				var pos = s + str.length;
				t.setSelectionRange(pos, pos);

			}
		}, true);
	});