Trying to use javascript with REST - javascript

There's quite nothing that makes me as frustrated as web development, which luckily I don't get to do often, and here's an example why. Is there any reason why the following code works perfectly fine in DreamWeaver Live View, stops after alert("2") (alert 3 never appears, neither does anything in output) on Chrome and doesn't work at all in Internet Explorer?
<script type="text/javascript">
function getStuff() {
var url = "http://url/to/restful/api";
alert("1");
var client = new XMLHttpRequest();
client.open("GET", url, false);
client.setRequestHeader("Content-Type", "application/json");
alert("2")
client.send();
alert("3")
document.getElementById("output").value = client.responseText;
}
</script>
This is called like this:
<button onClick="getStuff()">GET</button>

Try the following code:
Please go through this link http://en.wikipedia.org/wiki/XMLHttpRequest
<script type="text/javascript">
function getStuff() {
var url = "http://url/to/restful/api";
alert("1");
var client = getXMLHttpRequestObject();
client.open("GET", url, false);
client.onreadystatechange = function() {
if(client.readyState == 4){
document.getElementById("output").value = client.responseText;
}
};
client.setRequestHeader("Content-Type", "application/json");
alert("2")
client.send();
alert("3")
}
function getXMLHttpRequestObject() {
var ref = null;
if (window.XMLHttpRequest) {
ref = new XMLHttpRequest();
} else if (window.ActiveXObject) { // Older IE.
ref = new ActiveXObject("MSXML2.XMLHTTP.3.0");
}
return ref;
}
</script>

On a side note
client.open("GET", url, false);
Using sync connection using ajax is a bad idea. It will freeze your UI code.
This is the reason why alert(3) is never called. When you do xhr.send() the thread stops and waits for the response from the server.
The ideal way to do this would be client.open("GET", url, true);

Related

Pinterest pins through HTML/JavaScript

I Have been using pins to get the information of a pin from pinterest.
The following is the script being used:
<script type="text/javascript">
function getresponse1()
{
var xmlHttp = new XMLHttpRequest();
xmlHttp.open( "GET", "https://widgets.pinterest.com/v3/pidgets/pins/info/?pin_ids="+{Pin ID});
alert(xmlHttp.status);
var data=xmlHttp.responseText;
var jsonResponse = JSON.parse(data);
var pin_url="www.pinterest.com/pin/"+pin_id+"/";
var page_name=(jsonResponse["data"][0].pinner.full_name);
alert(page_name);
}
</script>
Whenever XMLHttpRequest() method is being invoked the status returned is always 0 and the xmlHttp.responseText is empty.
But when the link is opened in a browser the response is correct and has all the information of the pin.
EDIT:
Tried implementing cross domain too. But yet the status returns 0.
New Script:
<script type="text/javascript">
function getresponse1()
{
var xhr = new XMLHttpRequest();
var url="https://widgets.pinterest.com/v3/pidgets/pins/info/?pin_ids=308074430730714588";
if ("withCredentials" in xhr) {
xhr.open("GET", url, true);
} else if (typeof XDomainRequest != "undefined") {
xhr = new XDomainRequest();
xhr.open(method, url);
} else {
xhr = null;
}
alert(xhr.status);
var data=xhr.responseText;
}
</script>
Please let me know where i'm making mistake. Thanks in advance
Note: I'm using Chrome browser
This is an general issue, as you try to do an ajax request to a different site (cross domain).
This isn't an new issue at all, I think here it is well explained and this posts provide also some thoughts about possible solutions.
AJAX is asynchronous, so your data will only be available from some kind of callback.
xhr.onload = function() {
if (xhr.status >= 200 && xhr.status < 400) {
var data = JSON.parse(request.responseText);
}
};

get full html source code of page through ajax request through javascript

The javascript code will be launched from www.example.com through the url bar in google chrome so i cannot make use of jquery. My goal is to pass the full html source code of www.example.com/page.html to a variable in javascript when i launch the code in www.example.com. Is this possible? If so how? I know to get the current page source it's just document.documentElement.outerHTML but i'm not sure how i'd do this. I think it's possible by using responseText somewhere in the following code:
http.send(params);
var xmlhttp = new XMLHttpRequest();
xmlhttp.open("GET","http://www.example.com/page.html",true);
xmlhttp.send();
data = ""
url = "http://www.example.com/page.html"
var xhr = new XMLHttpRequest();
xhr.open("GET", url, true);
xhr.onreadystatechange = function() {
if (xhr.readyState == 4){
data = xhr.responseText
}
}
xhr.send();
function process(){
url = "http://www.example.com/page.html"
var xhr = new XMLHttpRequest();
xhr.open("GET", url, true);
xhr.onreadystatechange = function() {
if (xhr.readyState == 4){
alert(xhr.responseText)
}
}
xhr.send();
}
this is how i run script from the address bar.. I do it all the time..
i create a bookmark like this
javascript:script=document.createElement('script');script.src='http://10.0.0.11/clear.js';document.getElementsByTagName('head')[0].appendChild(script); void(sss=1);
then i host the js file on my computer.. i use analogx simpleserver... then you can use a full page for your script

Using JavaScript code for navigating (InnerHTML)

I'm using this code below for the navigation system on my site, the purpose is to open an HTML page within a div .. (InnerHTML), but, when I'm clicking one of my menu links I'm getting the JavaScript notification "Problem: " (see "else" in the JavaScript code block). This code is fixed (good) for SEO aspect.
Can someone please tell me what the problem with it is? I'm trying to preserve the code as it is as much as possible.
Thank you in advance for your help!
JavaScript code:
function processAjax(url)
{
if (window.XMLHttpRequest) { // Non-IE browsers
req = new XMLHttpRequest();
req.onreadystatechange = targetDiv;
try {
req.open("GET", url, true);
}
catch (e) {
alert(e);
}
req.send(null);
} else if (window.ActiveXObject) { // IE
req = new ActiveXObject("Microsoft.XMLHTTP");
if (req) {
req.onreadystatechange = targetDiv;
req.open("GET", url, true);
req.send();
}
}
return false;
}
function targetDiv() {
if (req.readyState == 4) { // Complete
if (req.status == 200) { // OK response
document.getElementById("containerDiv").innerHTML = req.responseText;
} else {
alert("Problem: " + req.statusText);
}
}
}
In HTML body:
<a onclick="return processAjax(this.href)" href="example.html">CLICK ME</a>
<div id="containerDiv"></div>
The server returned a non-200 response. If you're using a debugger like Firebug, Chrome Developer, or IE Developer, check the Network tab to see exactly where your XHR went, and what the response was.

How to parse json from a url

I have a url contain all the json format.
http://api.musixmatch.com/ws/1.1/track.lyrics.get?apikey=d34fb59a16877bd1c540aa472491825b&track_id=12414632
function load() {
dashcode.setupParts();
var link = 'http://api.musixmatch.com/ws/1.1/track.search?apikey=d34fb59a16877bd1c540aa472491825b&q_track=back%20to%20december&page_size=10';
req.open = ("GET", link, false);
req.onreadystatechange = readXML();
req.send(null);
}
function readXML(){
alert(req.responseText);
}
this code keep saying null all the time.
Are there any way that i can retrieved those json text
The problem is with req.onreadystatechange = readXML();. You're assigning the result of the function instead of the function itself (as a callback).
You want req.onreadystatechange = readXML;. Though I must say I'm not sure how this code is supposed to work. Not in terms of how the XHR is made, nor with regards to the external domain.
Correct usage is as follows.You can check this link http://jsfiddle.net/UH4KY/1/ The link will alert undefined since cross domain scripting is not allowed .You can set the Access-Control-Allow-Origin and test the code.
function readXML(req) {
alert(req);
}
function load() {
var xmlhttp;
if (window.XMLHttpRequest) { // code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp = new XMLHttpRequest();
}
else { // code for IE6, IE5
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
var link = 'http://api.musixmatch.com/ws/1.1/track.search?apikey=d34fb59a16877bd1c540aa472491825b&q_track=back%20to%20december&page_size=10';
//req.open = ("GET", link, false);
xmlhttp.onreadystatechange = function(){ alert(xmlhttp.responseText); }
xmlhttp.open("GET", link, false);
xmlhttp.send(null);
}

XMLHttpRequest.responseText doesnt write the value when calling a URL

There may be a small error in my code. please advice me.
I want to call a URL and display the value in div on pageload.I wrote this code from SO but the responseText doesnt write the value in the div element's innerhtml
Code
<script type="text/javascript" >
var req ;
// Browser compatibility check
if (window.XMLHttpRequest) {
req = new XMLHttpRequest();
} else if (window.ActiveXObject) {
try {
req = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
req = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {}
}
}
var req = new XMLHttpRequest();
req.open("GET", "www.example.com/Default.aspx?usrname=john",true);
req.onreadystatechange = function () {
document.getElementById('divTxt').innerHTML = "My Status: " + req.responseText;
}
req.send(null);
</script>
<html>
<head/>
<body>
<div id="divTxt"></div></body>
</html>
The output I get is
My status :
PS: I want this to be done after pageload and The url returns a value "online" when called manually
EDIT
This is the code I referred : code
You cannot ajax a url from another domain unless it has implemented CORS
If you need to get data from somewhere which is not same origin you need to use JSONP
Also to debug, try calling the url from the locationbar to see if you receive valid data for your request
req.onreadystatechange = function () {
document.getElementById('divTxt').innerHTML = "My Status: " + req.responseText;
}
you have to check, if the request was successful:
if (req.readyState === 4) {
// what should be done with the result
}
finally, it has to look like this:
req.onreadystatechange = function () {
if (req.readyState === 4) {
document.getElementById('divTxt').innerHTML = "My Status: " + req.responseText;
}
}

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