centrer mes pages dans mon design

bonjour voilà la petit probléme quand je réalise mon script avec un iframe cela fonction du tonner avec target="centre avec les div cela ne fonctionne pas pq svp?? voici le code
Code:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
<html>
<head>
 <script type="text/javascript">
/* --- www.easy-micro.com --- */
if (this.name!='fullscreen')
{
window.open(location.href,'fullscreen','fullscreen,scrollbars')
}
</script>
<style>
#centre {
background-color:#9999CC;
margin-left: 150px;
margin-right: 150px;
}
#haut {
width: 700px;
margin-left: auto;
margin-right: auto;
height: 30px;
}
.menuhaut {
list-style-type: none;
margin: 0;
padding:0;
}
.menuhaut li {
display: inline;
}
.menuhaut a {
margin: 0 2px;
color: #000000;
text-decoration: underline;
}
.menuhaut a:hover {
text-decoration: none;
}
</style>
</head>
<body>
<div align="center">
  <table width="800" height="500" border="0" cellpadding="0" cellspacing="0">
    <tr>
      <td width="30"><img src="design/clone.jpg" width="30" height="30"></td>
      <td width="714"><img src="design/barred.jpg" width="740" height="30"></td>
      <td width="30"><img src="design/clone1.jpg" width="30" height="30"></td>
    </tr>
    <tr>
      <td width="30" height="30"><img src="design/barregp.jpg" width="30" height="30" /></td>
      <td width="714" bgcolor="#993399"><div id="haut">
 
	<ul class="menuhaut">
	<li><a href="forum/page1.html" target="centre" title="page1">Menu 1</a></li>
	<li><a href="page2.html" target="centre" title="page2">Menu 2</a></li>
	<li><a href="page3.html" target="centre" title="page3">Menu 3</a></li>
	<li><a href="">Menu 4</a></li>
        </ul>
 
	</div></td>
      <td width="30"><img src="design/barredrp.jpg" width="30" height="30" /></td>
    </tr>     
    <tr>
      <td width="30"><img src="design/barregp.jpg" width="30" height="100" /></td>
      <td width="714"><img src="design/h1.jpg" width="740" height="100" /></td>
      <td width="30"><img src="design/barredrp.jpg" width="30" height="100" /></td>
    </tr>    
    <tr>
      <td width="10" bgcolor="#FFB400"><img src="design/barreg.jpg" width="30" height="470" /></td>
      <td width="714" bgcolor="#FFB400" align="center"><div align="center">
        <table width="100%" height="470" border="5" bordercolor="#4A0078">
          <tr>
            <td height="10">&nbsp;</td>
            <td height="10" align="center">nnn</td>
            <td height="10">&nbsp;</td>
          </tr>
          <tr>
            <td width="120">&nbsp;</td>
          <div id="centre"><td width="450" align="center"name="centre" id="centre" ></td></div>
              <td width="140"><iframe name="listuser" id="listuser" height="100%" width="100%" src="default.html" scrolling="auto" class="normal"></iframe></td>
            </tr>
        </table>
      </div></td>
      <td width="30" bgcolor="#FFB400"><img src="design/barredr.jpg" width="30" height="470"></td>
    </tr>
    <tr>
      <td width="30"><img src="design/cloned.jpg" width="30" height="30"></td>
         <td width="714" ><img src="design/barreb.jpg" width="740" height="30"></td>
         <td width="30"><img src="design/clone1d.jpg" width="30" height="30"></td>
    </tr>
  </table>
</div>
</body>
</html>