Develop Reference

HTML Creation Through For-loop Not Working Entirely

This is my code:
let info = document.getElementById('info');
let week = document.getElementById('week');
/*Initializer Function*/
window.addEventListener('load', () => {
let long;
let lat;
if (navigator.geolocation) {
navigator.geolocation.getCurrentPosition(position => {
long = position.coords.longitude;
lat = position.coords.latitude;
const proxy = 'https://cors-anywhere.herokuapp.com/';
const api = `${proxy}https://api.darksky.net/forecast/d571a1e2483b31605b94edaae84c647e/${lat},${long}`;
let xhr = new XMLHttpRequest();
xhr.onreadystatechange = function () {
if (this.readyState === 4 && this.status === 200) {
let obj = JSON.parse(this.responseText);
console.log(obj);
document.getElementById('temperature-degree').innerHTML = obj.currently.apparentTemperature;
document.getElementById('location').innerHTML = obj.timezone;
document.getElementById('temperature-description').innerHTML = obj.currently.summary;
setIcons(obj.currently.icon, document.getElementById('currentDayIcon'));
for (let i = 0; i < obj.hourly.data.length; i++) {
info.innerHTML += `<div id='hour${i + 1}' class='hourly'>` + `<canvas id='hourIcon${i + 1}'></canvas>` + `<h3 id='hourTemp${i + 1}'></h3>` + `<p id='hourSummary${i + 1}'></p>` + '</div>';
setIcons(obj.hourly.data[i].icon, document.getElementById(`hourIcon${i + 1}`));
document.getElementById(`hourTemp${i + 1}`).innerHTML = obj.hourly.data[i].temperature;
document.getElementById(`hourSummary${i + 1}`).innerHTML = obj.hourly.data[i].summary;
}
for (let i = 0; i < 5; i++) {
week.innerHTML += `<div id='day${i + 1}' class='daily'>` + `<canvas id='dayIcon${i + 1}'></canvas>` + `<h2 id='dayTemp${i + 1}'></h2>` + `<p id='daySummary${i + 1}'></p>` + '</div>';
setIcons(obj.daily.data[i].icon, document.getElementById(`dayIcon${i + 1}`));
document.getElementById(`dayTemp${i + 1}`).innerHTML = obj.daily.data[i].temperatureMax;
document.getElementById(`daySummary${i + 1}`).innerHTML = obj.daily.data[i].summary;
}
}
};
xhr.open("GET", api, true);
xhr.send();
});
}
function setIcons(icon, iconId) {
const skycons = new Skycons({color: 'white'});
const currentIcon = icon.replace(/-/g, '_').toUpperCase();
skycons.play();
return skycons.set(iconId, Skycons[currentIcon]);
}
;
});
...and the problem is that when it comes to the icons being loaded and displayed it's only the last one that actually displays. I don't know what the problem is because if it's successful for the last one, then it should be successful for the previous 47 since the last is the same iteration done for the 48th time. Any ideas?

How to refresh image by setTimeout, when url is getting by ajax?

I am writing a REST client to remote api. And I am using xmlHTTPRequest to get information about images.I need to refresh my images in every 30 seconds. My implementation of setTimeout function doesn't work. Anyone can help me? Thank you in advance.
Here is my code: Image.js
function Camera(id, name, ip, port) {
var button = document.createElement("button");
button.classList.add("camera");
button.innerHTML += "<h3>" + name + "</h3><br>";
var ismin = true;
this.id = id;
this.name = name;
this.ip = ip;
this.port = port;
this.getURL = function getURL(min) {
var url = 'http://' + ip + ":8080/api";
return min ? url + '/miniature/' + id + '?t=' + new Date().getTime() : url + '/image/' + id + '?t=' + new Date().getTime();
};
this.appendImg = function appendImg(url) {
button.innerHTML = "<h3>" + name + '</h3><br><img src="' + url + '"/>';
setTimeout(appendImg(url),30000);
};
this.showElement = function showElement(url) {
this.appendImg(url);
var that = this;
document.querySelector('#camera-section').appendChild(button);
button.addEventListener('click', function () {
ismin = !ismin;
that.appendImg(that.getURL(ismin), false);
});
};}
And a part of main.js:
function showImage(response) {
response = JSON.parse(sessionStorage.getItem('camera'));
console.log(response);
for (var i = 0; i < response.length; i++) {
var a = response[i];
var camera = new Camera(a.cameraId, a.name, ip, port, true);
var curl = camera.getURL(true);
camera.showElement(curl);
}
}
xml.onreadystatechange = function () {
if (this.readyState == 4 && this.status == 200) {
var response = JSON.parse(this.responseText);
sessionStorage.setItem('camera',JSON.stringify(response));
//console.log(sessionStorage.getItem('camera'));
showImage(sessionStorage.getItem('camera'));
}
};
xml.open('GET', mainUrl);
xml.send(null);

Regarding the comment of Pranay Kumar, first part of your code could be like this::
function Camera(id, name, ip, port) {
var button = document.createElement("button");
button.classList.add("camera");
button.innerHTML += "<h3>" + name + "</h3><br>";
var ismin = true;
this.id = id;
this.name = name;
this.ip = ip;
this.port = port;
this.getURL = function getURL(min) {
var url = 'http://' + ip + ":8080/api";
return min ? url + '/miniature/' + id + '?t=' + new Date().getTime() : url + '/image/' + id + '?t=' + new Date().getTime();
};
this._appendImg = function(url) {
return function() {
button.innerHTML = "<h3>" + name + '</h3><br><img src="' + url + '"/>';
}
};
this._timerHandle = 0;
this.appendImg = function(url) {
if (this._timerHandle) {
clearInterval(this._timerHandle);
}
this._timerHandle = setInterval(this._appendImg(url),30000);
}
this.showElement = function showElement(url) {
this.appendImg(url);
var that = this;
document.querySelector('#camera-section').appendChild(button);
button.addEventListener('click', function () {
ismin = !ismin;
that.appendImg(that.getURL(ismin), false);
});
}
}

You want refresh image every 30 seconds.
So use setInterval instead of setTimeout

How to save the parameters value between functions call?

I'm trying to create a weather app, sending Ajax requests to OpenWeatherMap. I've got an error in w.getWeatherFunc, when I'm giving the function sendRequest the parameter of w.weather and then giving the same parameter to the function displayFunc, which I'm calling next.
Here is what I've got in the console:
Uncaught TypeError: Cannot read property 'weather' of undefined
at displayFunc (weather.js:46)
at weather.js:78
How can I fix this and make it work?
function Weather () {
var w = this;
var weatherUrl = 'http://api.openweathermap.org/data/2.5/weather?';
var appid = '&appid=c0a7816b2acba9dbfb70977a1e537369';
var googleUrl = 'https://maps.googleapis.com/maps/api/geocode/json?address=';
var googleKey = '&key=AIzaSyBHBjF5lDpw2tSXVJ6A1ra-RKT90ek5bvQ';
w.demo = document.getElementById('demo');
w.place = document.getElementById('place');
w.description = document.getElementById('description');
w.temp = document.getElementById('temp');
w.humidity = document.getElementById('humidity');
w.getWeather = document.getElementById('getWeather');
w.addCityBtn = document.getElementById('addCity');
w.rmCityBtn = document.getElementById('rmCity');
w.icon = document.getElementById('icon');
w.wind = document.getElementById('wind');
w.time = document.getElementById('time');
w.lat = null;
w.lon = null;
w.cityArray = [];
w.weather = null;
function sendRequest (url, data) {
var request = new XMLHttpRequest();
request.open('GET', url, true);
request.send();
request.onreadystatechange = function() {
if (request.readyState == 4 && request.status == 200) {
data = JSON.parse(request.responseText);
console.log(data);
return data;
} else {
console.log(request.status + ': ' + request.statusText);
}
}
}
function displayFunc (obj) {
console.log('obj ' + obj);
w.icon.src = 'http://openweathermap.org/img/w/' + obj.weather[0].icon + '.png';
var timeNow = new Date();
var hours = timeNow.getHours();
var minutes = timeNow.getMinutes() < 10 ? '0' + timeNow.getMinutes() : timeNow.getMinutes();
w.time.innerHTML = hours + ':' + minutes;
w.place.innerHTML = 'Place: ' + obj.name;
w.description.innerHTML = "Weather: " + obj.weather[0].description;
w.temp.innerHTML = "Temperature: " + w.convertToCels(obj.main.temp) + "°C";
w.humidity.innerHTML = "Humidity: " + obj.main.humidity + '%';
w.wind.innerHTML = 'Wind: ' + obj.wind.speed + ' meter/sec';
}
w.convertToCels = function(temp) {
var tempC = Math.round(temp - 273.15);
return tempC;
}
w.getWeatherFunc = function() {
if (navigator.geolocation) {
navigator.geolocation.getCurrentPosition(function(location){
w.lat = location.coords.latitude;
w.lon = location.coords.longitude;
var url = weatherUrl + 'lat=' + w.lat + '&lon=' + w.lon + appid;
var result = sendRequest(url, w.weather);
console.log(result);
displayFunc(result);
});
} else {
alert('Browser could not find your current location');
}
}
w.addCityBtn.onclick = function() {
var newCity = prompt('Please insert city', 'Kiev');
var gUrl = googleUrl + newCity + googleKey;
var newCityWeather = null;
sendRequest(url, newCityWeather);
var location = newCityWeather.results[0].geometry.location;
var newUrl = weatherUrl + 'lat=' + location.lat + '&lon=' + location.lng + appid;
sendRequest(newUrl, w.weather);
displayFunc(newCity);
w.cityArray.push(newCity);
}
window.onload = w.getWeatherFunc;
setInterval(function() {
w.getWeatherFunc();
}, 900000);
}

Your ajax return returns into the browsers engine. As its async you need to create a callback:
function sendRequest(url,data,callback){
//if the data was received
callback(data);
}
Use like this
sendRequest("yoururl",data,function(data){
displayFunc(data);
});

The first time you pass the obj to the function it will save it one scope higher. after that, if you don;t pass the object the one you saved earlier will be used.
var objBkp;
function displayFunc (obj) {
if(undefined === obj) obj = objBkp;
else objBkp = obj;
// rest of code here
}

In your sendRequest you are passing only the value of w.weather, not its reference. JavaScript doesn't pass variables by value or by reference, but by sharing. So if you want to give the value to your variable you should do this inside your function sendRequest:
request.onreadystatechange = function() {
if (request.readyState == 4 && request.status == 200) {
w.weather = JSON.parse(request.responseText);
console.log(data);
return data;
} else {
console.log(request.status + ': ' + request.statusText);
}
}
Also, if you are using the attributes, you don't have to pass them in the function as arguments. Besides that fact, it would be good if you also create get() and set()

What does the console.log(result); in getWeatherFunc gives you?
The problem as I see it is that in the displayFunc the parameter passed is undefined.

JavaScript variable not changing with XMLHttpRequest

I tried to run this but it doesn't work.
It is intended to return a variable assigned inside a function, that was passed as callback to sendRequest(), which is retrieving data from the Internet through XMLHttpRequest asynchronously.
Can anyone tell me why this is not working and always returning ""?
function sendRequest(requestCode, args, callback){
var req = requestEngineUrl + "?req=" + requestCode + ";" + args;
var xmlHttp = new XMLHttpRequest();
xmlHttp.onreadystatechange = function(){
if(xmlHttp.readyState == 4)
{
if(callback != null){
callback(xmlHttp.responseText);
}
}
};
xmlHttp.open("GET", req, true);
xmlHttp.send(null);
}
this.assembleProcess = function(){
if(!isNull(this.id) && !isNull(this.titles)){
var titles = this.titles;
var id = this.id;
c = "";
sendRequest('304', id,
function(result){
var res = result.split("/");
var title = res[0];
var possibilities = res[1];
var fcontent = title + '<br><div>';
if(titles.length != possibilities){
console.log("WARNING: [SURVEYCARD].titles has not the same length as possibilities");
}
for(i = 0; i < possibilities; i++){
fcontent += '<div><a onclick="sendRequest("301",' + id + ',' + i + ',null)">' + titles[i] + '</a></div>';
}
fcontent += '</div>';
c = fcontent;
});
return c;
}

As an XMLHttpRequest is async, you should write an async function for that matter, like this
this.assembleProcess = function(callback){
if(!isNull(this.id) && !isNull(this.titles)){
var titles = this.titles;
var id = this.id;
c = "";
sendRequest('304', id,
function(result){
var res = result.split("/");
var title = res[0];
var possibilities = res[1];
var fcontent = title + '<br><div>';
if(titles.length != possibilities){
console.log("WARNING: [SURVEYCARD].titles has not the same length as possibilities");
}
for(i = 0; i < possibilities; i++){
fcontent += '<div><a onclick="sendRequest("301",' + id + ',' + i + ',null)">' + titles[i] + '</a></div>';
}
fcontent += '</div>';
c = fcontent;
callback(c)
});
}
and then, instead of using this.assembleProcess as a function with a result, you should pass a function as parameter:
Instead of
console.log(this.assembleProcess);
do this
this.assembleProcess(function(c){console.log(c)});

How to make xmlhttprequest periodically?

I want to loop an httprequest every 5 seconds.
Here is my code :
var xmlhttp2 = new XMLHttpRequest();
var url2 = "http:...";
xmlhttp2.onreadystatechange = function() {
if (xmlhttp2.readyState == 4 && xmlhttp2.status == 200) {
var response2 = xmlhttp2.responseText;
var response2 = xmlhttp2.responseText;
var json2 = JSON.parse(response2);
for (var i = 2; i < json2.length; i++){
document.getElementById('table2').innerHTML += '<tr><td>' + json2[i].nm + '</td><td>' + json2[i].id + '</td><td id="uid_'+i+'">' + json2[i].stn + '</td></tr>';
}
}
xmlhttp2.open("GET", url2, true);
xmlhttp2.send();
I tried to put this whole code in a function and called
setInterval(myFunction,5000);
This works. However the table is displaying several times.
I tried
setInterval("xmlhttp2.send();",5000);
and this doesn't work. The request is made only once.
Any advice ?
Thank you

You can clear the table before populating it with the server response
Answer
var xmlhttp2 = new XMLHttpRequest();
var url2 = "http:...";
xmlhttp2.onreadystatechange = function() {
if (xmlhttp2.readyState == 4 && xmlhttp2.status == 200) {
var response2 = xmlhttp2.responseText;
var response2 = xmlhttp2.responseText;
var json2 = JSON.parse(response2);
var table = document.getElementById('table2');
table.innerHTML = '';
for (var i = 2; i < json2.length; i++){
table.innerHTML += '<tr><td>' + json2[i].nm + '</td><td>' + json2[i].id + '</td><td id="uid_'+i+'">' + json2[i].stn + '</td></tr>';
}
}
xmlhttp2.open("GET", url2, true);
xmlhttp2.send();
Use setInterval(myFunction,5000); to make periodic request.
Edited
var xmlhttp2 = new XMLHttpRequest();
var url2 = "http:...";
xmlhttp2.onreadystatechange = function() {
if (xmlhttp2.readyState == 4 && xmlhttp2.status == 200) {
var response2 = xmlhttp2.responseText;
var response2 = xmlhttp2.responseText;
var json2 = JSON.parse(response2);
var tableBody = document.getElementById('table2Body');
tableBody.innerHTML = '';
for (var i = 2; i < json2.length; i++){
tableBody.innerHTML += '<tr><td>' + json2[i].nm + '</td><td>' + json2[i].id + '</td><td id="uid_'+i+'">' + json2[i].stn + '</td></tr>';
}
}
xmlhttp2.open("GET", url2, true);
xmlhttp2.send();