Es verdad aprendi eso con el dream
te dejo el script
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<script language="JavaScript" type="text/JavaScript">
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function MM_findObj(n, d) { //v4.01
var p,i,x; if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
if(!x && d.getElementById) x=d.getElementById(n); return x;
}
function MM_showHideLayers() { //v6.0
var i,p,v,obj,args=MM_showHideLayers.arguments;
for (i=0; i<(args.length-2); i+=3) if ((obj=MM_findObj(args[i]))!=null) { v=args[i+2];
if (obj.style) { obj=obj.style; v=(v=='show')?'visible':(v=='hide')?'hidden':v; }
obj.visibility=v; }
}
//-->
</script>
Esta es lo que pusiste vos correjido
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<div id='pmateo' style='position: absolute; top: 60px; left: 84px; width: 225; height: 91; background-color:yellow; z-index:1; visibility: hidden; overflow: hidden;'>
<table border='1'><tr><td>
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
</td></tr></table>
</div>
<p> </p><table>
<tr>
<td> <a href="#" onclick="MM_showHideLayers('pmateo','','show')" onMouseOut="MM_showHideLayers('pmateo','','hide')" >Mate</a> </td>
</tr>
</table>