function showPage(contentPage)
{
    var url = "getValues.php"; 
  var myAjax = new Ajax.Request(url,
				{ 
				    method: 'post', 
				    onSuccess: processPage,
                                    parameters: {page: contentPage}
				});
}

function processPage(request)
{
	var mainContent = document.getElementById("mainContent");
	mainContent.innerHTML = request.responseText;
}