function noticeIt() {
var msg=document.getElementById("msgBox");
var when=document.getElementById("whenBox");
var where=document.getElementById("whereBox");
var who=document.getElementById("whoBox");
var what=document.getElementById("whatBox");
msg.innerHTML=when.value+"、"
+where.value+"で、"
+who.value+"が、"
+what.value+"をした。"
+"<br>がんばれ、"+who.value+"!"
}
<ul>
<li>いつ:<input type="text" id="whenBox" size="30"></li>
<li>どこで:<input type="text" id="whereBox" size="30"></li>
<li>誰が:<input type="text" id="whoBox" size="30"></li>
<li>何をした:<input type="text" id="whatBox" size="30"></li>
</ul>
<input type="button" value="出力!" onclick="noticeIt()"/>
<div id="msgBox">"</div>