Here, I hope it will help you.
1. Make an html in your theme folder.
(Make sure you file 100% is blank without codes)
theme_blocklogin.html
2. Copy & Paste this into theme_blocklogin.html
<{if $xoops_isuser}>
<div style="font:Verdana, Arial, Helvetica, sans-serif; font-size:10px; font-weight:bold; text-align:left ">
Hello <a href="<{$xoops_url}>/user.php"><{$xoops_uname}>a>!
div>
<{else}>
<form onkeyup="highlight(event)" onclick="highlight(event)" style="margin-top: 2px; margin-bottom: 0px" action="<{$xoops_url}>/user.php" method="post">
<input class="form" name="uname" onblur="if(this.value=='') this.value='Username';" onfocus="if(this.value=='Username') this.value='';" type="text" value="Username" size="10" />
<input class="form" onblur="if(this.value=='') this.value='Password';" onfocus="if(this.value=='Password') this.value='';" value="Password" name="pass" type="password" size="10" />
<input type="hidden" name="op" value="login" />
<input class="button" name="submit" type="submit" value="Login" />
form>
<{/if}>
3. Make another blank html in your theme folder
theme_blockjoin.html
4. Put this in
<{if $xoops_isuser}>
<div style="font:Verdana, Arial, Helvetica, sans-serif; font-size:10px; font-weight:bold; ">
<a href="<{$xoops_url}>/user.php?op=logout">Logouta>
div>
<{else}>
<form style="margin-top: 2px; margin-bottom: 0px" action="<{$xoops_url}>/register.php" method="post">
<input class="button" name="submit" type="submit" value=" Join " />
form>
<{/if}>
5. Save them
6. Open the theme.html
7. Make a table and cells
8. Use this code for the Login Box
<{include file="themeFOLDER/theme_blocklogin.html"}>
9. Use this for the Join button $ logout
<{include file="themeFOLDER/theme_blockjoin.html"}>
10. Save them and upload it.
Info:
Before user login or guest will only see the login box such as username and pass, login button and the join button.
After user logged in they see the welcome message and the logout button.
Before:
------------------------------
| User | Pass [login] [join] |
------------------------------
After:
------------------------------
| Welcome, username [logout] |
------------------------------
You can make this script into a block mode or into your theme.
You can also customize the welcome msg in the theme_blocklogin.html
The real example:
http://test.maxmzone.com