billedeknap enter halløj problem IGEN!

man kan ikke trykke enter på knappen selvom den er markeret via "Tab"...  den virker med museknappen....
Kør selv hele koden igennem og se problemet...det er ret mærkeligt.. (!bemærk adresselinjen!)
________________________________

<script type="text/javascript">
var d = document;
function LoginBoxPassFocus(A,B)
{
    A.style.display = "none";
    B.style.display = "inline";
    B.focus();
}
function LoginBoxExit()
{
    if(d.getElementById("password").value == '')
    {
        d.getElementById("password").style.display = "none";
        d.getElementById("dapasstxt").style.display = "inline";
    }
}
function LoginBoxPassFocus(A,B)
{
    A.style.display = "none";
    B.style.display = "inline";
    B.focus();
}
function LoginBoxExit()
{
    if(d.getElementById("password").value == '')
    {
        d.getElementById("password").style.display = "none";
        d.getElementById("dapasstxt").style.display = "inline";
    }
}
</script>
<script type="text/javascript"> 
//Encrypted Password script- By Rob Heslop
//Script featured on Dynamic Drive
//Visit http://www.dynamicdrive.com

function submitentry(){
password = document.login.password.value.toLowerCase()
username = document.login.username.value.toLowerCase()
passcode = 1
usercode = 1
for(i = 0; i < password.length; i++) {
passcode *= password.charCodeAt(i);
}
for(x = 0; x < username.length; x++) {
usercode *= username.charCodeAt(x);
}
if(usercode==145645456400&&passcode==160687546456436500000)
{
window.location=password+".htm"}
else{
alert("Forkert kodeord/brugernavn!")}
}
</script>

<form name="login">
          <div align="center">
            <b>Login:</b>
          </div>
          <div align="center">

        </div>
          <div align="center">
       
            <input type="text" tabindex="1" name="username" value="Brugernavn" onfocus="if(this.value=='Brugernavn')this.value='';" onblur="if(this.value=='')this.value='Brugernavn';" class="inputfield" size="10"/>
           
            <input type="text" tabindex="2" name="dapasstxt" id="dapasstxt" value="Password" onfocus="LoginBoxPassFocus(this,this.form.password);" class="inputfield" size="10"/>
           
            <input type="password" tabindex="2" name="password" id="password" onblur="LoginBoxExit();" class="inputfield" style="display:none;" size="10" onclick="submitentry()"/>

            <img src="../../grafik/loginknap_1.gif" onmouseover="this.src='../../grafik/loginknap_2.gif'" onmouseout="this.src='../../grafik/loginknap_1.gif'" onclick="submitentry()" tabindex="3">

<input type="submit" value="" style="display: inline; border: #ffffff 0px solid;">
            </div>
        </form>