WaldeMar1321,
<!DOCTYPE HTML>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
</head>
<body>
<p class="text">Some text</p>
<p class="text">Some another text</p>
<textarea id="comment" cols="30" rows="10"></textarea>
<select name="" id="sel1">
<option value="0">Общая информация</option>
<option value="1">Главные задачи</option>
</select>
<a href="#" class="go">Опубликовать</a>
<script>
window.addEventListener("DOMContentLoaded", function() {
var b = document.querySelector("#sel1"),
a = document.querySelector(".go"),
d = document.querySelector("#comment"),
c = document.querySelectorAll(".text");
a.addEventListener("click", function(a) {
a.preventDefault();
c[+b.value].innerHTML += d.value
})
});
</script>
</body>
</html>