var
	httpRequestNavigationStr = false;

/**
 * Returns the navigation string by calling the pagenavigation Ajax request.
 */
function getNavigationStr() {
	httpRequestNavigationStr = false;
	httpRequestNavigationStr = createXMLHttpRequest();
	if (!httpRequestNavigationStr) {
		if (showMessage) showMessage('error.xmlhttp.navigation');
		return false;
	}

	httpRequestNavigationStr.onreadystatechange = navigationStrCallback;
	httpRequestNavigationStr.open('GET', 'pagenavigation?form=' + currentForm.toUpperCase() + '&page=' + currentPage, true);
	httpRequestNavigationStr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
	httpRequestNavigationStr.send(null);
}

/**
 * The callback for the pagenavigation Ajax request.
 */
function navigationStrCallback() {
	if (httpRequestNavigationStr.readyState == 4) {
		if (httpRequestNavigationStr.status == 200) {
			eval(httpRequestNavigationStr.responseText);
			if (sessionTimeout) {
				sessionTimeoutEvent.timeout.fire();
			} else {
				var pageNavigation = document.getElementById('page_navigation');
				pageNavigation.innerHTML = pageNavigationStr;
			}
		} else {
			if (showMessage) showMessage('error.request.navigation', httpRequestNavigationStr.status);
		}
	}
}