I want to view and manipulate Javascript localStorage information on a PHP page using PHP. I have gotten pretty far with this, but I'm not where I need to be. I'm using PHP 7.3 and vanilla JS.
I have AJAX POSTing the data to a PHP processing page (not the one that calls the javascript function). However, I need to access the POST variable on the page that called the javascript. How can I pass the information back without a click?
The page wishlist.php contains a link to the js file and <div id="temporary_wishlist"></div>.
Javascript called from wishlist.php:
window.addEventListener("load", function() {
loadWishlist();
});
// get wishlist contents
function loadWishlist() {
var items = wishlistStorage.data.items.join("%20");
var item_notes = wishlistStorage.data.item_notes.join("%20");
var comments = wishlistStorage.data.comments;
var wishlistRequest;
var response = null;
if(window.XMLHttpRequest) {
wishlistRequest = new XMLHttpRequest();
} else {
wishlistRequest = new ActiveXObject("Microsoft.XMLHTTP");
}
wishlistRequest.onreadystatechange = function() {
if(wishlistRequest.readyState == 4 && wishlistRequest.status == 200) {
response = wishlistRequest.responseText;
document.getElementById("temporary_wishlist").innerHTML = response;
}
}
wishlistRequest.open("POST", "/wishlist-processor.php", true);
wishlistRequest.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
wishlistRequest.send("wishlist_items=" + encodeURIComponent(items)
+ "&wishlist_itemnotes=" + encodeURIComponent(item_notes)
+ "&wishlist_comments=" + encodeURIComponent(comments));
}
Given the above, I have access to $_POST['wishlist_items'] inside wishlist-processor.php. Whatever I output inside of wishlist-processor.php is visible to the visitor on wishlist.php inside <div id="temporary_wishlist"></div>. It is not, however, visible in the Console.
On wishlist.php, I want to load the information into a PHP variable so I can send it to a MySQL query. If I could just POST to self like I do with form validation I would have access to $_POST['wishlist_items'] from wishlist.php. I already tried setting the URL in the open("POST", URL, true) function to _self or wishlist.php, and that didn't work for me.
I know it's suggested that I use Fetch, but I'm already overwhelmed learning new things I want to understand AJAX better. Also, Fetch doesn't work on Firefox Android.
I'm trying to retrieve the online status of users from a chat client called IMVU(the regular little image holder by the profile pictures isn't enough, I'm making something bigger, so I need some signal), and the way to do that is use this line of the user ID 1111111 for example:
http://avatars.imvu.com/catalog/web_status_updater.php?ol=1&list=1111111
It returns a php file containing a line of JSON. I need that whole line of text put into a javascript variable so I can use it.
I need to use this in a script I'm making, but I can't seem to get it to work. I've tried lots of things, the closest seems to be this one:
function readTextFile(file)
{
var rawFile = new XMLHttpRequest();
rawFile.open("GET", file, false);
rawFile.onreadystatechange = function ()
{
if(rawFile.readyState === 4)
{
if(rawFile.status === 200 || rawFile.status == 0)
{
var allText = rawFile.responseText;
alert(allText);
}
}
}
rawFile.send(null);
}
readTextFile("http://avatars.imvu.com/catalog/web_status_updater.php?ol=1&list=1111111");
(I'll change the alert(allText); to return allText; or return rawFile.responseText; when I get this experiment to work first and make sure that the text is actually stored and displayed.)
What happens is that the alert shows up blank. Just a white box, that's all. My prior attempts had the box show up and it said "undefined", but now it's doing something I guess? Why is it blank though? And how do I fix it?
EDIT:
It works in IE but not Firefox apparently.
I believe the problem here is the Same Origin Policy. You are attempting to make a request to a domain that is different than the one that originated the request.
Some websites specify headers which allow this, but the headers returned here are missing the Access-Control-Allow-Origin header.
One way around this is to use JSON-P on servers that support it.
Try this:
jQuery.ajax({
url:"http://avatars.imvu.com/catalog/web_status_updater.php?ol=1&list=1111111",
dataType:"jsonp"
})
.done(function(data) {
console.log(data)
});
I'm writing a ColdFusion application that fills with some HTML content some divs once the corresponding button is clicked.
What happens is that the readyState never goes up from the initial state of 1.
The fact that makes me crazy is that I used the same AJAX code in other modules that work fine.
I tried manually the code in my applet "___AJAX_load_translator.cfm" to see if works correctly (inputting a complete url with parameters and query string) and it works.
I put many alerts in these javascript functions to trace if the url was created correctly, the parameters were formatted correctly and so on. Everything seems fine. This is driving me crazy. The result is the same on FireFox and IE.
function getHTTPObject(){
if (window.ActiveXObject) return new ActiveXObject("Microsoft.XMLHTTP");
else
if (window.XMLHttpRequest) return new XMLHttpRequest();
else {
alert("No AJAX support.");
return null;
}
}
function setOutput(divID){
if(httpObject.readyState == 4 && httpObject.status == 200){
document.getElementById(divID).innerHTML = httpObject.responseText;
} // else alert(httpObject.readyState + ' ' + httpObject.status);
}
function loadeditor(divID,CP,PP){
<CFOUTPUT>var CF_TOKENS = "CFID=#CFID#&CFTOKEN=#CFTOKEN#";</CFOUTPUT>
var operativeurl= "___AJAX_load_translator.cfm?"+CF_TOKENS+"&CP="+CP+"&PP="+PP;
httpObject = getHTTPObject();
if (httpObject != null) {
httpObject.open("POST", operativeurl, true);
httpObject.onreadystatechange = setOutput(divID);
httpObject.send(null);
}
}
I noticed that, putting an alert into the setOutput function, it displays a sudden readystate of 1. Then the browser statusbar shows the status of wait for a call to the server, that disappears quite immediately. It seems that the call is really done in that moment, and probably it is imho.
But it seems to me that after that readyness of the call (state 1) there is no more proceeding. It seems somehow blocked. Or, the function setOutput is deactivated. Maybe a second change to a state of 4 happens and this state is not registered by the callback ? In this case, why the DIV is not updated with the new content ?
Thanks for any help.
httpObject.onreadystatechange = setOutput(divID);
^^^^^^^
You're calling/executing your setouput function right then and there, and whatever the function returns becomes on the onreadystatechange callback "pointer".
Remove the (divID) portion, so you assign the function itself, not whatever it returns:
httpObject.onreadystatechange = setOutput;
I'm using an AJAX function to transfer data to a PHP file. The data that I'm passing to the AJAX function is 17000 characters long. This is generally too long to transfer using the GET method, however one would think that the POST method would allow for such large variables to be be passed on.
Here's the AJAX function I'm using:
function ajaxFunction(id, datatypeString, pathToFileString, variable){
var myRequestObject = null;
document.getElementById(id).innerHTML = "<span>Started...</span>";
if (window.XMLHttpRequest)
{
myRequestObject = new XMLHttpRequest();
}
else if (window.ActiveXObject)
{
try
{
myRequestObject = new ActiveXObject("Msxml2.XMLHTTP");
}
catch (e)
{
try
{
myRequestObject = new ActiveXObject("Microsoft.XMLHTTP");
}
catch (e) {}
}
}
myRequestObject.onreadystatechange = function()
{
document.getElementById(id).innerHTML = "<span>Wait server...</span>";
if(myRequestObject.readyState == 4)
{
if(myRequestObject.status == 200)
{
// process a document here
document.getElementById(id).innerHTML = "<span>Processing file...</span>"
if(datatypeString == "txt"){
//Injects code from a text file
document.getElementById(id).innerHTML = myRequestObject.responseText;
}
else if(datatypeString == "xml"){
//Injects code from an XML file
document.getElementById(id).innerHTML = myRequestObject.responseXML.documentElement.document.getElementsByTagName('title')[0].childNodes[0].nodeValue; // Inject the content into the div with the relevant id
}
else{
document.getElementById(id).innerHTML = "<span>Datatype exception occured</span>";
}
}
else
{
document.getElementById(id).innerHTML = "<span>Error: returned status code " + myRequestObject.status + " " + myRequestObject.statusText + "</span>";
}
}
};
myRequestObject.open("POST", pathToFileString+variable, true);
myRequestObject.send(null);
}
And this is the function call to that AJAX function:
ajaxFunction("myDiv", "txt", "processdata.php", "?data="+reallyLargeJavascriptVariable);
Also this is the error that I'm getting when the AJAX function is called:
Error: returned status code 414 Request-URI Too Large
I've looked around on Stackoverflow and other websites for a solution to this problem. However most answers come down to: "Use the POST method instead of the GET method to transfer the data."
However as you can see in the AJAX function, I'm already using the POST method.
So I'm not sure what's going on here and what to change in my code to solve this issue. I simply want to be able to pass very large variables to my function, but with this function that doesn't seem possible.
Given the error, the limitations of the URI seem to be causing the problem. However, I'm using the POST method and not the GET method, so why is the variable still passed via the URI? Since I am not using the GET method, but rather the POST method like many people suggested in other threads about this problem, I'm not sure why the URI is involved here and is seemingly causing a problem.
Apparently the URI is putting a limit on the size of the variable that I can transfer, however I'm using the POST method, so why is this error occurring and how can I adjust my AJAX function to make it work with the large variables that I want to transfer using AJAX?
When you're doing a POST you need to pass the POST data on the .send (you're currently passing null). You need to set a few header details, as well.
myRequestObject.open("POST", pathToFileString, true);
myRequestObject.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
myRequestObject.setRequestHeader("Content-length", variable.length);
myRequestObject.send(variable);
If you're currently passing a question mark in the start of variable or end of the path go ahead and remove it.
I can detect when the content of an iframe has loaded using the load event. Unfortunately, for my purposes, there are two problems with this:
If there is an error loading the page (404/500, etc), the load event is never fired.
If some images or other dependencies failed to load, the load event is fired as usual.
Is there some way I can reliably determine if either of the above errors occurred?
I'm writing a semi-web semi-desktop application based on Mozilla/XULRunner, so solutions that only work in Mozilla are welcome.
If you have control over the iframe page (and the pages are on the same domain name), a strategy could be as follows:
In the parent document, initialize a variable var iFrameLoaded = false;
When the iframe document is loaded, set this variable in the parent to true calling from the iframe document a parent's function (setIFrameLoaded(); for example).
check the iFrameLoaded flag using the timer object (set the timer to your preferred timeout limit) - if the flag is still false you can tell that the iframe was not regularly loaded.
I hope this helps.
This is a very late answer, but I will leave it to someone who needs it.
Task: load iframe cross-origin content, emit onLoaded on success and onError on load error.
This is the most cross browsers origin independent solution I could develop. But first of all I will briefly tell about other approaches I had and why they are bad.
1. iframe That was a little shock for me, that iframe only has onload event and it is called on load and on error, no way to know it is error or not.
2. performance.getEntriesByType('resource'). This method returns loaded resources. Sounds like what we need. But what a shame, firefox always adds Resource in resources array no matter it is loaded or failed. No way to know by Resource instance was it success. As usual. By the way, this method does not work in ios<11.
3. script I tried to load html using <script> tag. Emits onload and onerror correctly, sadly, only in Chrome.
And when I was ready to give up, my elder collegue told me about html4 tag <object>. It is like <iframe> tag except it has fallbacks when content is not loaded. That sounds like what we are need! Sadly it is not as easy as it sounds.
CODE SECTION
var obj = document.createElement('object');
// we need to specify a callback (i will mention why later)
obj.innerHTML = '<div style="height:5px"><div/>'; // fallback
obj.style.display = 'block'; // so height=5px will work
obj.style.visibility = 'hidden'; // to hide before loaded
obj.data = src;
After this we can set some attributes to <object> like we'd wanted to do with iframe. The only difference, we should use <params>, not attributes, but their names and values are identical.
for (var prop in params) {
if (params.hasOwnProperty(prop)) {
var param = document.createElement('param');
param.name = prop;
param.value = params[prop];
obj.appendChild(param);
}
}
Now, the hard part. Like many same-like elements, <object> doesn't have specs for callbacks, so each browser behaves differently.
Chrome. On error and on load emits load event.
Firefox. Emits load and error correctly.
Safari. Emits nothing....
Seems like no different from iframe, getEntriesByType, script....
But, we have native browser fallback! So, because we set fallback (innerHtml) directly, we can tell if <object> is loaded or not
function isReallyLoaded(obj) {
return obj.offsetHeight !== 5; // fallback height
}
/**
* Chrome calls always, Firefox on load
*/
obj.onload = function() {
isReallyLoaded(obj) ? onLoaded() : onError();
};
/**
* Firefox on error
*/
obj.onerror = function() {
onError();
};
But what to do with Safari? Good old setTimeout.
var interval = function() {
if (isLoaded) { // some flag
return;
}
if (hasResult(obj)) {
if (isReallyLoaded(obj)) {
onLoaded();
} else {
onError();
}
}
setTimeout(interval, 100);
};
function hasResult(obj) {
return obj.offsetHeight > 0;
}
Yeah.... not so fast. The thing is, <object> when fails has unmentioned in specs behaviour:
Trying to load (size=0)
Fails (size = any) really
Fallback (size = as in innnerHtml)
So, code needs a little enhancement
var interval = function() {
if (isLoaded) { // some flag
return;
}
if (hasResult(obj)) {
if (isReallyLoaded(obj)) {
interval.count++;
// needs less then 400ms to fallback
interval.count > 4 && onLoadedResult(obj, onLoaded);
} else {
onErrorResult(obj, onError);
}
}
setTimeout(interval, 100);
};
interval.count = 0;
setTimeout(interval, 100);
Well, and to start loading
document.body.appendChild(obj);
That is all. I tried to explain code in every detail, so it may look not so foolish.
P.S. WebDev sucks
I had this problem recently and had to resort to setting up a Javascript Polling action on the Parent Page (that contains the IFRAME tag). This JavaScript function checks the IFRAME's contents for explicit elements that should only exist in a GOOD response. This assumes of course that you don't have to deal with violating the "same origin policy."
Instead of checking for all possible errors which might be generated from the many different network resources.. I simply checked for the one constant positive Element(s) that I know should be in a good response.
After a pre-determined time and/or # of failed attempts to detect the expected Element(s), the JavaScript modifies the IFRAME's SRC attribute (to request from my Servlet) a User Friendly Error Page as opposed to displaying the typical HTTP ERROR message. The JavaScript could also just as easily modify the SRC attribute to make an entirely different request.
function checkForContents(){
var contents=document.getElementById('myiframe').contentWindow.document
if(contents){
alert('found contents of myiframe:' + contents);
if(contents.documentElement){
if(contents.documentElement.innerHTML){
alert("Found contents: " +contents.documentElement.innerHTML);
if(contents.documentElement.innerHTML.indexOf("FIND_ME") > -1){
openMediumWindow("woot.html", "mypopup");
}
}
}
}
}
I think that the pageshow event is fired for error pages. Or if you're doing this from chrome, then your check your progress listener's request to see if it's an HTTP channel in which case you can retrieve the status code.
As for page dependencies, I think you can only do this from chrome by adding a capturing onerror event listener, and even then it will only find errors in elements, not CSS backgrounds or other images.
Doesn't answer your question exactly, but my search for an answer brought me here, so I'm posting just in case anyone else had a similar query to me.
It doesn't quite use a load event, but it can detect whether a website is accessible and callable (if it is, then the iFrame, in theory, should load).
At first, I thought to do an AJAX call like everyone else, except that it didn't work for me initially, as I had used jQuery. It works perfectly if you do a XMLHttpRequest:
var url = http://url_to_test.com/
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status != 200) {
console.log("iframe failed to load");
}
};
xhttp.open("GET", url, true);
xhttp.send();
Edit:
So this method works ok, except that it has a lot of false negatives (picks up a lot of stuff that would display in an iframe) due to cross-origin malarky. The way that I got around this was to do a CURL/Web request on a server, and then check the response headers for a) if the website exists, and b) if the headers had set x-frame-options.
This isn't a problem if you run your own webserver, as you can make your own api call for it.
My implementation in node.js:
app.get('/iframetest',function(req,res){ //Call using /iframetest?url=url - needs to be stripped of http:// or https://
var url = req.query.url;
var request = require('https').request({host: url}, function(response){ //This does an https request - require('http') if you want to do a http request
var headers = response.headers;
if (typeof headers["x-frame-options"] != 'undefined') {
res.send(false); //Headers don't allow iframe
} else {
res.send(true); //Headers don't disallow iframe
}
});
request.on('error',function(e){
res.send(false); //website unavailable
});
request.end();
});
Have a id for the top most (body) element in the page that is being loaded in your iframe.
on the Load handler of your iframe, check to see if getElementById() returns a non null value.
If it is, iframe has loaded successfully. else it has failed.
in that case, put frame.src="about:blank". Make sure to remove the loadhandler before doing that.
If the iframe is loaded on the same origin as the parent page, then you can do this:
iframeEl.addEventListener('load', function() {
// NOTE: contentDocument is null if a connection error occurs or if
// X-Frame-Options is not SAMESITE (which could happen with
// 4xx or 5xx error pages if the corresponding error handlers
// do not specify SAMESITE). If error handlers do not specify
// SAMESITE, then networkErrorOccurred will incorrectly be set
// to true.
const networkErrorOccurred = !iframeEl.contentDocument;
const serverErrorOccurred = (
!networkErrorOccurred &&
!iframeEl.contentDocument.querySelector('#well-known-element')
);
if (networkErrorOccurred || serverErrorOccurred) {
let errorMessage;
if (networkErrorOccurred) {
errorMessage = 'Error: Network error';
} else if (serverErrorOccurred) {
errorMessage = 'Error: Server error';
} else {
// Assert that the above code is correct.
throw new Error('networkErrorOccurred and serverErrorOccurred are both false');
}
alert(errorMessage);
}
});