go/doc/codelab/wiki/edit.html

<h1>Editing {{.Title |html}}</h1>

<form action="/save/{{.Title |html}}" method="POST">
<div><textarea name="body" rows="20" cols="80">{{printf "%s" .Body |html}}</textarea></div>
<div><input type="submit" value="Save"></div>
</form>