Reading a response in javascript from JSP - javascript

I am new in learning AJAX and stuck in the first program. Tried to debug but unable to do so.
Below is my code snippet
----------input-ajax.html-------------------
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>HTML PAGE</title>
<script type="text/javascript">
var request=null;
function createRequest(){
try{
request= new XMLHttpRequest();
)catch(e){
try{
request=new ActiveXObject("Msxml2.XMLHTTP");
}catch(e){
try{
request= new ActiveXObject("Microsoft.XMLHTTP");
}catch(failed){
request=null;
}
}
}
if(request==null){
alert("Error Creating Request Object");
}
}
function getName(){
alert("getname called");
createRequest();
var url = "showName-ajax.jsp";
request.open("POST",url,true);
alert("before");
request.onreadystatechange = updatePage;
alert("after");
request.send(null);
}
function updatePage(){
//var newName= request.getResponseHeader("r1");
var newName= request.responseText;
var name1 = document.getElementById("name");
replaceText(name1,newName);
}
function replaceText(el, text) {
if (el != null) {
clearText(el);
var newNode = document.createTextNode(text);
el.appendChild(newNode);
}
}
function clearText(el) {
if (el != null) {
if (el.childNodes) {
for (var i = 0; i < el.childNodes.length; i++) {
var childNode = el.childNodes[i];
el.removeChild(childNode);
}
}
}
}
</script>
</head>
<body>
<h1>WELCOME <span id="name"> GUEST</span></h1>
<form method="POST">
<input type="text" name="t1">
<input type="button" value="Show Name" onclick="getName();"/>
</form>
</body>
</html>
----------showName-ajax.jsp------------
<%
String s1=request.getParameter("t1");
response.setContentType("text/plain");
response.setCharacterEncoding("UTF-8");
response.getWriter().write(s1); // Write response body.
%>
But When I run the program (click on the button) nothing happens. Even the alert message that getName function is called does not appear. PLEASE HELP!!!!

Typo:
)catch(e){
should be
}catch(e){
This would show up as an error in the console of your browser. Be sure to always check that first if things don't work like they should.

You have a ) instead of a } here:
try{
request= new XMLHttpRequest();
)catch(e){
So your function never gets defined.

change )catch(e){ to }catch(e){
but
why are you creating request object everytime on button click?
you just need to call "createRequest()" only once on page load event.

Related

document.write() after window.onload [duplicate]

I am creating a simple ajax call that retrieves the content of a specified url and writes it to the page. The problem I am having is that it replaces the entire body contents with this information
here is the JS:
(function(){
var mb = window.mb = {};
function get_ad(url, parameters){
var result = "";
var http_request = false;
if (window.XMLHttpRequest) { // Mozilla, Safari,...
http_request = new XMLHttpRequest();
if (http_request.overrideMimeType) {
http_request.overrideMimeType('text/html');
}
} else if (window.ActiveXObject) { // IE
var avers = ["Microsoft.XmlHttp", "MSXML2.XmlHttp", "MSXML2.XmlHttp.3.0", "MSXML2.XmlHttp.4.0", "MSXML2.XmlHttp.5.0"];
for (var i = avers.length -1; i >= 0; i--) {
try {
http_request = new ActiveXObject(avers[i]);
if (http_request){
break;
}
} catch(e) {}
}
}
if (!http_request) {
alert('Cannot create XMLHTTP instance');
return false;
}
http_request.onreadystatechange = function(){
if (http_request.readyState == 4) {
if (http_request.status == 200) {
gen_output(http_request.responseText);
} else {
alert('Error');
}
}
}
http_request.open('GET', url + parameters, true);
http_request.send(null);
}
function gen_output(ad_content){
document.write("<div id=\"mb_ad\">");
document.write(ad_content);
document.write("</div>");
}
get_ad("http://localhost/test/test.html", "");
})();
and here is the html:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
</head>
<body>
i am text before <br/>
<script type="text/javascript" src="mb.js"></script>
<br />
i am text after
</body>
</html>
using firebug to inspect, i do not see the text before or the text after, just the <div id="mb_ad"> and the content from the test.html page. If i remove the ajax call and just do 3 document.writes the text before and the text after will display properly. jQuery is not an option, I have to do this without the help of a large library as size and speed are of the essence.
You can't use document.write once the document has completed loading. If you do, the browser will open a new document that replaces the current.
Use the innerHTML property to put HTML code inside an element:
function gen_output(ad_content){
document.getElementById('mb_ad').innerHTML = ad_content;
}
Put the element before the script, so that you are sure that it exists when the callback function is called:
i am text before
<div id="mb_ad"></div>
i am text after
<script type="text/javascript" src="mb.js"></script>
It doesn't matter much where you place the script, as nothing will be written to the document where it is.
in case you cant control the remote script you might be able to write something like so:
<script>
var tmp = document.write;
document.write = function () {
document.getElementById('someId').innerHTML = [].concat.apply([], arguments).join('');
};
</script>
<script .....>
document.write = tmp;
Well it is a nasty hack but it seems to work...
var div = document.createElement('div');
div.id = 'mb_ad';
div.innerHTML = ad_content;
Now, you can append this node wherever you want it to be.
you can use <script>document.body.innerHTML+="//Your HTML Code Here";</script>
Same Leon Fedotov answer but more jQuery
{
var old_write = document.write;
var $zone = $('.zone.zone_' + name);
// redefine document.write in this closure
document.write = function () {
$zone.append([].concat.apply([], arguments).join(''));
};
// OA_output[name] contains dangerous document.write
$zone.html(OA_output[name]);
document.write = old_write;
}
I had the same problem with the following code :
$html[] = '<script>
if($("#mf_dialogs").length == 0) {
document.write("<div id=\"mf_dialogs\"></div>");
}
</script>';
The following code replaces document.write efficiently :
$html = '<div id="dialogHolder"></div>
<script>
if($("#mf_dialogs").length == 0) {
document.getElementById("dialogHolder").innerHTML="<div id=\"mf_dialogs\"></div>";
}
</script>';
The way you can emulate document.write somewhat is the following code:
<script>
(function(script) {
var parent = script.parentNode;
var node = document.createTextNode('Surprise!');
parent.replaceChild(node, script);
})(document.currentScript);
</script>
This way you can put arbitrary HTML in place of a script element. If you have a simpler case, like you can wrap a script in another tag, you can do even simpler version.
<script>
document.currentScript.parentElement.innerHTML = 'Surprise!';
</script>

Ajax won't Display on web page

I am currently trying to use a Ajax in netbeans using JavaScript and PHP file. The following code I should click the button and the contents of the php fill should appear but it doesn't. When I use firebug in firefox the response shows the full php file has returned but will not display on webpage. Why???
<%#page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<script>
function getXMLHttp() {
var xmlHttp
try {
//Firefox, Opera 8.0+, Safari
xmlHttp = new XMLHttpRequest();
}
catch (e) {
//Internet Explorer
try {
xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
}
catch (e) {
try {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
catch (e) {
alert("Your browser does not support AJAX!")
return false;
}
}
}
return xmlHttp;
}
function MakeRequest() {
var xmlHttp = getXMLHttp();
xmlHttp.onreadystatechange = function() {
if (xmlHttp.readyState == 4) {
HandleResponse(xmlHttp.responseText);
}
}
xmlHttp.open("GET", "ajax.php", true);
xmlHttp.send(null);
}
function HandleResponse(response) {
document.getElementById('ResponseDiv').innerHTML = response;
}
</script>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<input type='button' onclick='MakeRequest();' value='Use AJAX!!!!'/>
<div id='ResponseDiv'>
This is a div to hold the response.
</div>
</body>
</html>
My PHP file is
<?php
echo "This is a php response to your request!!!!!!";
?>
Apart from the fact that HTML code is barely decent, why not use jQuery?
<button id="get" onClick="return false;">jQuery get</button>
<div id="result"></div>
<script type="text/javascript">
$("#get").click(function() {
$.get( "ajax.php", function( data ) {
$( "#result" ).html( data );
});
});
</script>
PHP is server side and is not made to be run on the client side. Your response should come from a URL and not the contents of a file. Ensuring that your response contains on HTML and not PHP should lead you to your solution.
Try replacing your PHP file with
<p>This is a php response to your request!!!!!!</p>
If this enables you to show your content, you have your problem and solution.

Plain Javascript (no JQuery) to load a php file into a div

Hi I don't know javascript but I am required to use it in one of my templates. I was googling around and found a solution whic is like this:
My Index.php file.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Test</title>
<script type="text/javascript">
window.onload = function(){
document.getElementById("aside").innerHTML="<img src='loadingImage.gif'>";
if(XMLHttpRequest) var x = new XMLHttpRequest();
else var x = new ActiveXObject("Microsoft.XMLHTTP");
x.open("GET", "other_content_1.php", true);
x.send("");
x.onreadystatechange = function(){
if(x.readyState == 4){
if(x.status==200) document.getElementById("aside").innerHTML = x.responseText;
else document.getElementById("aside").innerHTML = "Error loading document";
}
}
}
</script>
</head>
<body>
<div id="aside">This is aside</div>
</body>
</html>
My other_content_1.php file
<div id='other-content-1'>
<?php echo 'This text is loading via php command'; ?>
</div>
As this is the only Javascript function in my site I see no reason to load additional JQuery for it. I am sure there must be a way to do this with plain JavaScript / ajax without the need to load JQuery. Can anybody suggest the correct syntax to do so?
I want to happen asynchronously while the page continues to load.
from http://www.tutorialspoint.com/ajax/ , using plain XHR (XmlHttpRequest)
function loadPage() {
var ajaxRequest;
try{
// Opera 8.0+, Firefox, Safari
ajaxRequest = new XMLHttpRequest();
}catch (e){
// Internet Explorer Browsers
try{
ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
}catch (e) {
try{
ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");
}catch (e){
// Something went wrong
alert("Your browser broke!");
return false;
}
}
}
ajaxRequest.onreadystatechange = function(){
if(ajaxRequest.readyState == 4){
var ajaxDisplay = document.getElementById('ajaxDiv');
ajaxDisplay.innerHTML = ajaxRequest.responseText;
}
}
ajaxRequest.open("GET", "ajax-example.php", true);
ajaxRequest.send(null);
}
loadPage();
Try this:
window.onload = function(){
aside = document.getElementById("aside");
aside.innerHTML="<img src='loadingImage.gif'>";
if(XMLHttpRequest) var x = new XMLHttpRequest();
else var x = new ActiveXObject("Microsoft.XMLHTTP");
x.open("GET", "other_content_1.php", true);
x.send();
x.onreadystatechange = function(){
if(x.readyState == 4){
if(x.status == 200) aside.innerHTML = x.responseText;
else aside.innerHTML = "Error loading document";
}
}
}
And it is cross browser compatible, you never need the extra 32KB just to make a simple function supported cross browser.

Bugg error in validation

Goal:
To enable display a pop up if validation was correct or failure.
Problem:
Somehow it doesn't want to make a
validation of the password.
I tried using Firebug but It can't make debugging for this code for some reason.
Before creating this validation I had this code before:
function validation() {
if (mittXHRobjekt.readyState == 4)
alert("Okey");
}
After doing more improvement by adding validation, The readyState don't work properly. All I did was to improve the function validation only.
The current code with validation is:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled 1</title>
<script type="text/javascript">
var mittXHRobjekt = null;
function skapaXHRobjekt() {
try {
XHRobjekt = new XMLHttpRequest();
} catch (err1) {
try {
XHRobjekt = new ActiveXObject("Microsoft.XMLHTTP");
} catch (err2) {
try {
XHRobjekt = new ActiveXObject("Msxml2.XMLHTTP");
} catch (err3) {
XHRobjekt = false;
}
}
}
return XHRobjekt;
}
function validation() {
if (mittXHRobjekt.readyState == 4) {
if (window.document.frmPassword.txtPassword.value == mittXHRobjekt.responseText) {
alert("Correct password");
}
else {
alert("Wrong password");
}
}
alert("no ready state 4");
}
function test(url) {
mittXHRobjekt = skapaXHRobjekt();
if (mittXHRobjekt) {
mittXHRobjekt.onreadystatechange = validation;
mittXHRobjekt.open("GET", url);
mittXHRobjekt.send(null);
}
}
</script>
</head>
<body>
<form id="frmPassword">
<input name="txtPassword" type="password" />
<input name="btnPassword" type="button" value="Evaluation" onclick="test('password.txt')" />
</form>
</body>
</html>

JavaScript Document.Write Replaces All Body Content When Using AJAX

I am creating a simple ajax call that retrieves the content of a specified url and writes it to the page. The problem I am having is that it replaces the entire body contents with this information
here is the JS:
(function(){
var mb = window.mb = {};
function get_ad(url, parameters){
var result = "";
var http_request = false;
if (window.XMLHttpRequest) { // Mozilla, Safari,...
http_request = new XMLHttpRequest();
if (http_request.overrideMimeType) {
http_request.overrideMimeType('text/html');
}
} else if (window.ActiveXObject) { // IE
var avers = ["Microsoft.XmlHttp", "MSXML2.XmlHttp", "MSXML2.XmlHttp.3.0", "MSXML2.XmlHttp.4.0", "MSXML2.XmlHttp.5.0"];
for (var i = avers.length -1; i >= 0; i--) {
try {
http_request = new ActiveXObject(avers[i]);
if (http_request){
break;
}
} catch(e) {}
}
}
if (!http_request) {
alert('Cannot create XMLHTTP instance');
return false;
}
http_request.onreadystatechange = function(){
if (http_request.readyState == 4) {
if (http_request.status == 200) {
gen_output(http_request.responseText);
} else {
alert('Error');
}
}
}
http_request.open('GET', url + parameters, true);
http_request.send(null);
}
function gen_output(ad_content){
document.write("<div id=\"mb_ad\">");
document.write(ad_content);
document.write("</div>");
}
get_ad("http://localhost/test/test.html", "");
})();
and here is the html:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
</head>
<body>
i am text before <br/>
<script type="text/javascript" src="mb.js"></script>
<br />
i am text after
</body>
</html>
using firebug to inspect, i do not see the text before or the text after, just the <div id="mb_ad"> and the content from the test.html page. If i remove the ajax call and just do 3 document.writes the text before and the text after will display properly. jQuery is not an option, I have to do this without the help of a large library as size and speed are of the essence.
You can't use document.write once the document has completed loading. If you do, the browser will open a new document that replaces the current.
Use the innerHTML property to put HTML code inside an element:
function gen_output(ad_content){
document.getElementById('mb_ad').innerHTML = ad_content;
}
Put the element before the script, so that you are sure that it exists when the callback function is called:
i am text before
<div id="mb_ad"></div>
i am text after
<script type="text/javascript" src="mb.js"></script>
It doesn't matter much where you place the script, as nothing will be written to the document where it is.
in case you cant control the remote script you might be able to write something like so:
<script>
var tmp = document.write;
document.write = function () {
document.getElementById('someId').innerHTML = [].concat.apply([], arguments).join('');
};
</script>
<script .....>
document.write = tmp;
Well it is a nasty hack but it seems to work...
var div = document.createElement('div');
div.id = 'mb_ad';
div.innerHTML = ad_content;
Now, you can append this node wherever you want it to be.
you can use <script>document.body.innerHTML+="//Your HTML Code Here";</script>
Same Leon Fedotov answer but more jQuery
{
var old_write = document.write;
var $zone = $('.zone.zone_' + name);
// redefine document.write in this closure
document.write = function () {
$zone.append([].concat.apply([], arguments).join(''));
};
// OA_output[name] contains dangerous document.write
$zone.html(OA_output[name]);
document.write = old_write;
}
I had the same problem with the following code :
$html[] = '<script>
if($("#mf_dialogs").length == 0) {
document.write("<div id=\"mf_dialogs\"></div>");
}
</script>';
The following code replaces document.write efficiently :
$html = '<div id="dialogHolder"></div>
<script>
if($("#mf_dialogs").length == 0) {
document.getElementById("dialogHolder").innerHTML="<div id=\"mf_dialogs\"></div>";
}
</script>';
The way you can emulate document.write somewhat is the following code:
<script>
(function(script) {
var parent = script.parentNode;
var node = document.createTextNode('Surprise!');
parent.replaceChild(node, script);
})(document.currentScript);
</script>
This way you can put arbitrary HTML in place of a script element. If you have a simpler case, like you can wrap a script in another tag, you can do even simpler version.
<script>
document.currentScript.parentElement.innerHTML = 'Surprise!';
</script>

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