I'm using one main iFrame with targeted navigation and it's NOT WORKING. Works in chrome, not firefox, not IE. I click a navigation link and it opens in a new tab, instead of opening in the target iframe. Heres what i'm working with:

Code:
<div id="DivHome"> <a href="arcade.php" target="mainframe"><strong><font color="white">Home</font></strong></a></div>
<div id="DivConstruction"> <a href="under_construction.php" target="mainframe"><strong><font color="white">Construction</font></strong></a></div>
and heres my iframe.

Code:
<iframe scrolling="no" SRC="arcade.php" marginwidth="0" marginheight="0" frameborder="0" vspace="0" hspace="0" width="100%" height="100%" id="_iframe">
aaand my style.css.

Code:
#DivHome {
	position:absolute;
	left:42px;
	top:113px;
	width:39px;
	height:21px;
	font-size: 16pt;
	font-family:Tahoma, Geneva, sans-serif;
}
a {
	font-size: 14px;
	color: #FFF;
}
a:visited {
	color: #000;
	text-decoration: none;
}
a:hover {
	color: #0F0;
	text-decoration: underline;
}
a:active {
	color: #000;
	text-decoration: none;
}
a:link {
	color: #FFF;
	text-decoration: none;
}
body,td,th {
	color: #000;
}



#DivConstruction {
	position:absolute;
	left:91px;
	top:113px;
	width:50px;
	height:21px;
	font-size: 16pt;
	font-family:Tahoma, Geneva, sans-serif;
}
a {
	font-size: 14px;
	color: #FFF;
}
a:visited {
	color: #000;
	text-decoration: none;
}
a:hover {
	color: #0F0;
	text-decoration: underline;
}
a:active {
	color: #000;
	text-decoration: none;
}
a:link {
	color: #FFF;
	text-decoration: none;
}
body,td,th {
	color: #000;
	text-align: left;
}
Please help? I know it is something really silly, it has to be. Just can't figure it out.