function getWindowDimension(){
	return {height: $(window).height(),width: $(window).width()};
}

function getElementDimension(elem){
	if (typeof(elem)!="object"){elem="#"+elem}
	return {
        height: $(elem).height(),
        width: $(elem).width()
    };
}

function redimToCenter(objdiv){
    var wdim = getWindowDimension();
    var objcentro=$("#"+objdiv).get(0);
    var objdim = getElementDimension(objcentro);
    var centroTop = Math.abs((wdim.height - objdim.height * 2) / 2);
    var centroLeft = (wdim.width - objdim.width) / 2;
	$(objcentro).css("top", parseInt(centroTop * 100 / wdim.height) + "%");
    $(objcentro).css("left",parseInt(centroLeft * 100 / wdim.width) + "%");
    $(objcentro).css("visibility","visible");

}