搞了半天就是搞不出模式对话框的全屏显示，原来其与window.open的参数设置完全不同.
function winModalFullScreen(strURL)
{
var sheight = screen.height-70;
var swidth = screen.width-10;
var winoption ="dialogHeight:"+sheight+"px;dialogWidth:"+ swidth +"px;status:yes;scroll:yes;resizable:yes;center:yes";
var tmp=window.showModalDialog(strURL,window,winoption);
return tmp;
}
function winOpenFullScreen(strURL)
{
var sheight = screen.height-70;
var swidth = screen.width-10;
var winoption ="left=0,top=0,height="+sheight+",width="+swidth+",toolbar=yes,menubar=yes,location=yes,status=yes,scrollbars=yes,resizable=yes";
var tmp=window.open(strURL,'',winoption);
return tmp;
}