var xmlhttp;
function sendRequest_isbn(id) {
    // Native
    if (window.XMLHttpRequest) {
        xmlhttp = new XMLHttpRequest();
    // ActiveX
    } else if (window.ActiveXObject) {
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
        if (xmlhttp) { 
	} else {
		xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
	}
    }

        xmlhttp.onreadystatechange = handleResponse;
	var id = document.forms["formular"].elements["isbn"].value;
    	if (id != '') {
        	xmlhttp.open('get', '/lib/ajax/ajaxisbn.php?type=isbn&id='+ id);
        	xmlhttp.send(null);
	}
}

function sendRequest_titel(id) {
    // Native
    if (window.XMLHttpRequest) {
        xmlhttp = new XMLHttpRequest();
    // ActiveX
    } else if (window.ActiveXObject) {
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
        if (xmlhttp) { 
	} else {
		xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
	}
    }

        xmlhttp.onreadystatechange = handleResponse;
	var id = document.forms["formular"].elements["titel"].value;
    	if (id != '') {
        	xmlhttp.open('get', '/lib/ajax/ajaxisbn.php?type=titel&id='+ id);
        	xmlhttp.send(null);
	}
}

function sendRequest_autor(id) {
    // Native
    if (window.XMLHttpRequest) {
        xmlhttp = new XMLHttpRequest();
    // ActiveX
    } else if (window.ActiveXObject) {
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
        if (xmlhttp) { 
	} else {
		xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
	}
    }

        xmlhttp.onreadystatechange = handleResponse;
	var id = document.forms["formular"].elements["autor"].value;
    	if (id != '') {
        	xmlhttp.open('get', '/lib/ajax/ajaxisbn.php?type=autor&id='+ id);
        	xmlhttp.send(null);
	}
}

function handleResponse() {
        if ((xmlhttp.readyState == 4) && (xmlhttp.status == 200)) {
              document.getElementById('isbnSelect').innerHTML = xmlhttp.responseText;
        }
}