function wopen(url, win_name, width, height){
    posY=(screen.height-height)/2;
    posX=(screen.width-width)/2;

    window.open(url,
	        win_name,
		'width=' + width + ', height=' + height + ', ' +
		'left=' + posX + ', top=' + posY + ', ' + 
		'location=no, menubar=no, ' +
		'status=no, toolbar=no, scrollbars=yes, resizable=yes');
    return false;
}

/* function wopen(url,win_name,width,height){
    posY=(screen.height-ht)/2;
    posX=(screen.width-wt)/2;
    window.open(url,win_name,"width="+width+",height="+height+
    ",top="+posY+",left="+posX+",toolbar=no, location=no, directories=no, status=no, menubar=no, scrollbars=yes");

    return false;
 }*/