[jquery] jQuery add text to span within a div

<div id="tagscloud">
       <span></span>
</div>

How would I do to add some text within the span like code below ?

<span>**tag cloud**</span>

Edit: actually the span has an id

<div id="tagscloud"> <span id="WebPartCaptionWPQ2"></span> </div>

You can use append or prepend

The .append() method inserts the specified content as the last child of each element in the jQuery collection (To insert it as the first child, use .prepend()).

$("#tagscloud span").append(second);
$("#tagscloud span").append(third);
$("#tagscloud span").prepend(first);

Careful - append() will append HTML, and you may run into cross-site-scripting problems if you use it all the time and a user makes you append('<script>alert("Hello")</script>').

Use text() to replace element content with text, or append(document.createTextNode(x)) to append a text node.