TalkPHP - newb in javascript need help

hi, im doing this from a book and its not working what am i doing wrong?

here is my code
when i click on the first or second button i get this error

getvalue() is not defined

or

getValueTagName is not defined
onclick(click clientX=0, clientY=0)

Code:

<html>

<head>

<script type="text/javascript">



function getValueID() {



var byid = document.getElementById("listitems");

alert(byid[1]); //displays undefined

alert(byid.innerHTML); //displays all of ul's li items

alert(byid.parentNode); // parent node

alert(byid.childNotes[2];// shows second li item

alert(byid.firstChild); // shows first li

alert(byid.lastChild);// shows last li

alert(byid.nextSibling);

alert(byid.lastSibling);



}



function getValueTagName() {



var bytag = document.getElementByTagName("li");

alert(bytag[1]);





}



function getattrib() {



var link = document.getElementbyId("listitems");

alert(link.getAttribute("link");





}



</script>

</head>

<body>

<a href="http://google.com" id="link">google</a><br>



<ul id="listitems">

<li>first</li>

<li>second</li>

<li>third</li>

</ul>



<input type="submit" value="getValueID" onclick="getValueID()"/><br>

<input type="submit" value="getValueTagName" onclick="getValueTagName()"/><br>

<input type="submit" value="getAttribute" onclick="getattrib()"/><br>







</body>

</html>