When I use hardcoded JSON string, my UI comes OK
But when I use string from Web Service, no css style runs !!!
//jsonData = '{.....}';
//extractData(jsonData); //THIS CODE WORKS
var request = new XMLHttpRequest();
request.open("GET",url);
request.onload = function(){
if(request.status == 200){
jsonData = new String(request.responseText);
alert("RESPONSE : "+jsonData);
extractData(jsonData); //THIS WON'T WORK :(
}
else
alert("Connection Issue : "+request.status);
};
request.send(null);
Can anyone point out the root cause ???
I am running this code in phoneGap for Android.
Related
I am making a Pokedex API as a side project and I can not display the data needed to display in the different text boxes. I am using a GET request to request the height, weight, type, and ability.
<script>
$("button").click( function(){
var pokemonName = $('pokemon').val(pokemon);
event.preventDefault();
getPokemonData(pokemonName);
})
function getPokemonData(pokemonName){
var request = new XMLHttpRequest()
//GET request with link
request.open('GET','https://pokeapi.co/api/v2/pokemon/' + pokemonName, true);
// request for data
request.onload =function(){
var data = JSON.parse(this.response)
if(request.status >= 200 && request.status <= 400)
{
// outputs data
$(pokemonheight).val(response.height)
$(pokemonweight).val(response.weight)
$(pokemonAblity).val(response.ability)
$(pokemonType).val(response.type)
}
else
{
alert ("Error");
}
request.send();
}
}
</script>
</html>
I have tried setting a variable that would be equal to the response JSON element and then input that into the value of the textbox.
I do not have anything returned as expected or input displayed in the console if declared.
Issue(s)
There were a few issues with your code:
var pokemonName = $('pokemon').val(pokemon); you are setting the value of some element named pokemon (not valid) here
var data = JSON.parse(this.response); where is this.response being set? Shouldn't we be receiving response in the callback?
request.send(); is inside of the onload event, so the request never gets sent
Critiques
My main critique here is that you included a fairly large library (jQuery), and didn't utilize it to make the request. $.ajax is well documented and cleans up a lot of the intricacies of XMLHttpRequest.
The solution
$("button").click(function() {
var pokemonName = $('#pokemon').val();
//event.preventDefault();
getPokemonData(pokemonName);
})
function getPokemonData(pokemonName) {
var request = new XMLHttpRequest()
//GET request with link
request.open('GET', 'https://pokeapi.co/api/v2/pokemon/' + pokemonName, true);
// request for data
request.onload = function(response) {
var data = JSON.parse(response.currentTarget.response)
if (request.status >= 200 && request.status <= 400) {
// outputs data
console.log(data)
} else {
alert("Error");
}
}
request.send();
}
<input id="pokemon" value="12" />
<button>search</button>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
Taking all the above issues into account, I was able to get a working example of what it should ultimately look like.
Hope this helps!
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);
}
};
I have my servlet sending the following response to a JS ajax call:
response.setContentType("text/plain");
PrintWriter out = response.getWriter();
out.print("start");
out.close();
and the call from the web page has the following code:
function update() {
var xmlhttp = new XMLHttpRequest();
var id = '${user.id}';
var height = (window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight);
height = height-40;
var params = "action=update&id=" + id + "&height=" + height;
xmlhttp.open("POST", "/Anabasis/UserControl", true);
xmlhttp.setRequestHeader("Content-type",
"application/x-www-form-urlencoded");
xmlhttp.setRequestHeader("Content-length", params.length);
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
var answer = xmlhttp.responseText;
if(answer=="start"){
window.location.href = "/project/page1.jsp";
} else {
window.location.href = "/project/page2.jsp";
}
}
};
xmlhttp.send(params);
}
setTimeout(update, 10000);
If start is send back by the Servlet, the browser should be redirected to another page. This may be done without the user's doing anything since the JS request is send every 10 seconds.
Now the result is that I do not get the answer to page but just a black page with the text: "start"
Can anyone tell me what to add in order to asure that the answer gets back to the JS function?
It's better to forward your request according to your requirement, like:
RequestDispatcher rd=request.getRequestDispatcher("./project/page1.jsp");
rd.forward(request, response);
I have found the solution, sorry for the question. The code actually works fine, just in some case the Servlet gets not called by this update function but by another form from the same page. So of course the answer is not send to the function, explaining the misbehaviour.
Is there any guide on best practices concerning Servlet-Webpage communication? I guess I shall need that very much.
I want to upload a file trough a XMLHttpRequest. i have looked everywhere for examples and found quite a few. But i cant figer out what it is i am doing wrong. This is my code. The function is triggerd when a button is pressed. It not wrapped in from tags
function upl_kost() {
var url = "proces_data.php?ref=upload_kost";
var hr;
var file = document.getElementById("file_kost");
var formData = new FormData();
formData.append("upload", file.files[0]);
if (window.XMLHttpRequest) {
hr=new XMLHttpRequest();
} else {
hr=new ActiveXObject("Microsoft.XMLHTTP");
}
hr.open("POST", url, true);
hr.setRequestHeader("Content-type", "multipart/form-data");
hr.onreadystatechange = function() {
if(hr.readyState == 4 && hr.status == 200) {
var return_data = hr.responseText;
alert(return_data);
}
}
hr.send(formData);
}
and this function catches it.
if($_GET['ref'] == 'upload_kost') {
var_dump($_FILES);
}
My problem is that the $_FILES stays empty. When i look at the file.files variable in the js its loaded with the data from the file that i am trying to upload.
Thanks!
Reduce your JavaScript down to minimum required for this, then add in some helpful messages you can look in your console for
function upl_kost() {
var xhr = new XMLHttpRequest(),
url = 'proces_data.php?ref=upload_kost',
fd = new FormData(),
elm = document.getElementById('file_kost');
// debug <input>
if (!elm)
console.warn('Element not found');
else if (!(elm instanceof HTMLInputElement))
console.warn('Element not an <input>');
else if (!elm.files || elm.files.length === 0)
console.warn('<input> has no files');
else
console.info('<input> looks okay');
// end debug <input>
fd.append('upload', elm.files[0]);
xhr.addEventListener('load', function () {
console.log('Response:', this.responseText);
});
xhr.open('POST', url);
xhr.send(fd);
}
If you're still having a problem, it may be server-side, e.g. are you performing a redirect before trying to access $_FILES?
Your problem is that you're setting the content type of the request
hr.setRequestHeader("Content-type", "multipart/form-data");
If you ever saw a multipart/formdata post you'll notice the content type header has a boundary
Content-Type: multipart/form-data; boundary=----webko2354645675756
which is missing from your code.
If you do not set the content type header the browser will correctly set it and the required boundary. This will allow the server to properly parse the request body.
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