I have a trigger set up in Google Sheets so a URL is automatically opened in a new browser window. This works if the URL is hardcoded. I want the URL to be a variable. How do I pass the URL variable from Apps Script to HTML script? I'm a novice coder so please explain like I'm 5.
This function works if the URL is text like 'https://www.google.com'
function openMap() {
var maplink = SpreadsheetApp.getActiveSheet().getRange("B2").getValues();
var js = "<script>window.open('https://www.google.com', '_blank', 'width=800, height=600');google.script.host.close();</script>";
var html = HtmlService.createHtmlOutput(js)
.setHeight(10)
.setWidth(100);
SpreadsheetApp.getUi().showModalDialog(html, 'Now loading.');
}
This function does not if the URL is a variable (I checked the maplink value and its a valid URL)
function openMap() {
var maplink = SpreadsheetApp.getActiveSheet().getRange("B2").getValues();
var js = "<script>window.open('maplink', '_blank', 'width=800, height=600');google.script.host.close();</script>";
var html = HtmlService.createHtmlOutput(js)
.setHeight(10)
.setWidth(100);
SpreadsheetApp.getUi().showModalDialog(html, 'Now loading.');
}
You can join strings in the following manner:
...
var url = 'https://www.google.com';
var js = "<script>window.open('" + url + "', '_blank', 'width=800, height=600');google.script.host.close();</script>";
...
Basically
you close the first part of your hardcoded string by closing the quotes
add the dynamical variabl with +
continue the hardcoded string by appending the second part with + and opening the quotes again
I hope this is clear!
I want to make a RuneScape(an MMORPG Game) Name Checker. For this i am using an IRC bot. The URL i am using to check names is this- http://rscript.org/lookup.php?type=namecheck&name=
I am using javascript to take input and go to this url for checking names. The code i am using is this:
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">
function nameCheck()
{
var username = document.getElementById('uname').value;
var url = "http://rscript.org/lookup.php?type=namecheck&name=";
var curl = url + username;
}
</script>
</head>
<body>
<input class="textBox" id="uname" type="text" maxlength="15" required/>
<input type="button" onclick="nameCheck()" value="Submit">
</body>
</html>
To proceed with this i need a code that could check the output of the final url created ie.
curl. If the output page looks like this:
START
NAMECHECK: NOTAVALIBLE
SUGGESTIONS: blah blah blah
END
Then the code should run the function nameNotAva(). And if the output is like this:
START
NAMECHECK: AVALIBLE
END
Then the code should run the function nameAva().
The question:
I just want that using javascript the output be evalutaled to check that if NAMECHECK: NOTAVAILABLE is a part of the output page or not. If yes then a function nameNotAva() should be run. Otherwise a function nameAva() should be run.
Dont know what language u are using, with jQuery u can do following things
You can load the response inside a div.
function nameCheck()
{
var username = document.getElementById('uname').value;
var url = "http://rscript.org/lookup.php?type=namecheck&name=";
var curl = url + username;
var output = $('#someDiv').load( curl ).html() // .html() will give you the output or what the page
if( output.contains('NAMECHECK: NOTAVALIBLE'){ nameNotAva(); }
}
You can use simple AJAX and get the response text ( may be with async false)
function nameCheck()
{
var username = document.getElementById('uname').value;
var url = "http://rscript.org/lookup.php?type=namecheck&name=";
var curl = url + username;
$.ajax({
url : curl,
type : 'GET' //or 'POST',
success : function( urlOutput ){
if( urlOutput .contains('NAMECHECK: NOTAVALIBLE'){
nameNotAva();
}
}
});
}
I want do something: if something type url address like: www.mydomain.com/search(without request part), I want do something with javascript, fill with the url like www.mydomain.com/search?search=car, but nothing happened in my code.
<script>
var curent_url = document.URL;
if(document.URL.indexOf("?") < 0){ //if(!document.URL.match(/\?/)){
//alert('ok');
document.URL = curent_url+'?search=car';
}
</script>
Instead of document.URL, check for an empty document.location.search:
if (document.location.search.length === 0) {
// empty query string... append your part to doc
document.location.href = document.location.href + "?search=car";
}
Examine the document.location object in your console to see what else it offers. There's usually no need to parse out document.URL or document.location.href directly.
console.dir(document.location);
I have a link: Hello.
When someone clicks the link I'd like to check via JavaScript if the page the href-attribute points to exists or not. If the page exists the browser redirects to that page ("www.example.com" in this example) but if the page doesn't exist the browser should redirect to another URL.
It depends on whether the page exists on the same domain or not. If you're trying to determine if a page on an external domain exists, it won't work – browser security prevents cross-domain calls (the same-origin policy).
If it is on the same domain however, you can use jQuery like Buh Buh suggested. Although I'd recommend doing a HEAD-request instead of the GET-request the default $.ajax() method does – the $.ajax() method will download the entire page. Doing a HEAD request will only return the headers and indicate whether the page exists (response codes 200 - 299) or not (response codes 400 - 499). Example:
$.ajax({
type: 'HEAD',
url: 'http://yoursite.com/page.html',
success: function() {
// page exists
},
error: function() {
// page does not exist
}
});
See also: http://api.jquery.com/jQuery.ajax/
A pretty good work around is to proxy. If you don't have access to a server side you can use YQL. Visit: http://developer.yahoo.com/yql/console/
From there you can do something like: select * from htmlstring where url="http://google.com". You can use the "REST query" they have on that page as a starting point for your code.
Here's some code that would accept a full URL and use YQL to detect if that page exists:
function isURLReal(fullyQualifiedURL) {
var URL = encodeURIComponent(fullyQualifiedURL),
dfd = $.Deferred(),
checkURLPromise = $.getJSON('http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20htmlstring%20where%20url%3D%22' + URL + '%22&format=json');
checkURLPromise
.done(function(response) {
// results should be null if the page 404s or the domain doesn't work
if (response.query.results) {
dfd.resolve(true);
} else {
dfd.reject(false);
}
})
.fail(function() {
dfd.reject('failed');
});
return dfd.promise();
}
// usage
isURLReal('http://google.com')
.done(function(result) {
// yes, or request succeded
})
.fail(function(result) {
// no, or request failed
});
Update August 2nd, 2017
It looks like Yahoo deprecated "select * from html", although "select * from htmlstring" does work.
Based on the documentation for XMLHttpRequest:
function returnStatus(req, status) {
//console.log(req);
if(status == 200) {
console.log("The url is available");
// send an event
}
else {
console.log("The url returned status code " + status);
// send a different event
}
}
function fetchStatus(address) {
var client = new XMLHttpRequest();
client.onreadystatechange = function() {
// in case of network errors this might not give reliable results
if(this.readyState == 4)
returnStatus(this, this.status);
}
client.open("HEAD", address);
client.send();
}
fetchStatus("/");
This will however only work for URLs within the same domain as the current URL. Do you want to be able to ping external services? If so, you could create a simple script on the server which does your job for you, and use javascript to call it.
If it is in the same domain, you can make a head request with the xmlhttprequest object [ajax] and check the status code.
If it is in another domain, make an xmlhttprequest to the server and have it make the call to see if it is up.
why not just create a custom 404 handler on the web server? this is probably the more "good-bear" way to do this.
$.ajax({
url: "http://something/whatever.docx",
method: "HEAD",
statusCode: {
404: function () {
alert('not found');
},
200: function() {
alert("foundfile exists");
}
}
});
If you are happy to use jQuery you could do something like this.
When the page loads make an ajax call for each link. Then just replace the href of all the links which fail.
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"></script>
<script type="text/javascript">
<!--
$.fn.checkPageExists = function(defaultUrl){
$.each(this, function(){
var $link = $(this);
$.ajax({
url: $link.attr("href"),
error: function(){
$link.attr("href", defaultUrl);
}
});
});
};
$(document).ready(function(){
$("a").checkPageExists("default.html");
});
//-->
</script>
You won't be able to use an ajax call to ping the website because of same-origin policy.
The best way to do it is to use an image and if you know the website you are calling has a favicon or some sort of icon to grab, you can just use an html image tag and use the onerror event.
Example:
function pingImgOnWebsite(url) {
var img = document.createElement('img');
img.style.visibility = 'hidden';
img.style.position = 'fixed';
img.src = url;
img.onerror = continueBtn; // What to do on error function
document.body.appendChild(img);
}
Another way to do this is is with PHP.
You could add
<?php
if (file_exists('/index.php'))
{
$url = '/index.php';
} else {
$url = '/notindex.php';
}
?>
And then
<a href="<?php echo $url; ?>Link</a>
I want to reload an image on a page if it has been updated on the server. In other questions it has been suggested to do something like
newImage.src = "http://localhost/image.jpg?" + new Date().getTime();
to force the image to be re-loaded, but that means that it will get downloaded again even if it really hasn't changed.
Is there any Javascript code that will cause a new request for the same image to be generated with a proper If-Modified-Since header so the image will only be downloaded if it has actually changed?
UPDATE: I'm still confused: if I just request the typical URL, I'll get the locally cached copy. (unless I make the server mark it as not cacheable, but I don't want to do that because the whole idea is to not re-download it unless it really changes.) if I change the URL, I'll always re-download, because the point of the new URL is to break the cache. So how do I get the in-between behavior I want, i.e. download the file only if it doesn't match the locally cached copy?
Javascript can't listen for an event on the server. Instead, you could employ some form of long-polling, or sequential calls to the server to see if the image has been changed.
You should have a look at the xhr.setRequestHeader() method. It's a method of any XMLHttpRequest object, and can be used to set headers on your Ajax queries. In jQuery, you can easily add a beforeSend property to your ajax object and set up some headers there.
That being said, caching with Ajax can be tricky. You might want to have a look at this thread on Google Groups, as there's a few issues involved with trying to override a browser's caching mechanisms. You'll need to ensure that your server is returning the proper cache control headers in order to be able to get something like this to work.
One way of doing this is to user server-sent events to have the server push a notification whenever the image has been changed. For this you need a server-side script that will periodically check for the image having been notified. The server-side script below ensures that the server sends an event at least once every (approximately) 60 seconds to prevent timeouts and the client-side HTML handles navigation away from and to the page:
sse.py
#!/usr/bin/env python3
import time
import os.path
print("Content-Type: text/event-stream\n\n", end="")
IMG_PATH = 'image.jpg'
modified_time = os.path.getmtime(IMG_PATH)
seconds_since_last_send = 0
while True:
time.sleep(1)
new_modified_time = os.path.getmtime(IMG_PATH)
if new_modified_time != modified_time:
modified_time = new_modified_time
print('data: changed\n\n', end="", flush=True)
seconds_since_last_send = 0
else:
seconds_since_last_send += 1
if seconds_since_last_send == 60:
print('data: keep-alive\n\n', end="", flush=True)
seconds_since_last_send = 0
And then your HTML would include some JavaScript code:
sse.html
<html>
<head>
<meta charset="UTF-8">
<title>Server-sent events demo</title>
</head>
<body>
<img id="img" src="image.jpg">
<script>
const img = document.getElementById('img');
let evtSource = null;
function setup_sse()
{
console.log('Creating new EventSource.');
evtSource = new EventSource('sse.py');
evtSource.onopen = function() {
console.log('Connection to server opened.');
};
// if we navigate away from this page:
window.onbeforeunload = function() {
console.log('Closing connection.');
evtSource.close();
evtSource = null;
};
evtSource.onmessage = function(e) {
if (e.data == 'changed')
img.src = 'image.jpg?version=' + new Date().getTime();
};
evtSource.onerror = function(err) {
console.error("EventSource failed:", err);
};
}
window.onload = function() {
// if we navigate back to this page:
window.onfocus = function() {
if (!evtSource)
setup_sse();
};
setup_sse(); // first time
};
</script>
</body>
</html>
Here am loading an image, tree.png, as binary data dynamically with AJAX and saving the Last-Modified header. Periodically (every 5 second in the code below). I issue another download request sending backup a If-Modified-Since header using the saved last-modified header. I check to see if data has been returned and re-create the image with the data if present:
<!doctype html>
<html>
<head>
<title>Test</title>
<script>
window.onload = function() {
let image = document.getElementById('img');
var lastModified = ''; // 'Sat, 11 Jun 2022 19:15:43 GMT'
function _arrayBufferToBase64(buffer) {
var binary = '';
var bytes = new Uint8Array(buffer);
var len = bytes.byteLength;
for (var i = 0; i < len; i++) {
binary += String.fromCharCode(bytes[i]);
}
return window.btoa( binary );
}
function loadImage()
{
var request = new XMLHttpRequest();
request.open("GET", "tree.png", true);
if (lastModified !== '')
request.setRequestHeader("If-Modified-Since", lastModified);
request.responseType = 'arraybuffer';
request.onload = function(/* oEvent */) {
lastModified = request.getResponseHeader('Last-Modified');
var response = request.response;
if (typeof response !== 'undefined' && response.byteLength !== 0) {
var encoded = _arrayBufferToBase64(response);
image.src = 'data:image/png;base64,' + encoded;
}
window.setTimeout(loadImage, 5000);
};
request.send();
}
loadImage();
};
</script>
</head>
<body>
<img id="img">
</body>
</html>
You can write a server side method which just returns last modified date of the image resource,
Then you just use polling to check for the modified date and then reload if modified date is greater than previous modified date.
pseudo code (ASP.NET)
//server side ajax method
[WebMethod]
public static string GetModifiedDate(string resource)
{
string path = HttpContext.Current.Server.MapPath("~" + resource);
FileInfo f = new FileInfo(path);
return f.LastWriteTimeUtc.ToString("yyyy-dd-MMTHH:mm:ss", CultureInfo.InvariantCulture);//2020-05-12T23:50:21
}
var pollingInterval = 5000;
function getPathFromUrl(url) {
return url.split(/[?#]/)[0];
}
function CheckIfChanged() {
$(".img").each(function (i, e) {
var $e = $(e);
var jqxhr = $.ajax({
type: "POST",
contentType: "application/json; charset=utf-8",
url: "/Default.aspx/GetModifiedDate",
data: "{'resource':'" + getPathFromUrl($e.attr("src")) + "'}"
}).done(function (data, textStatus, jqXHR) {
var dt = jqXHR.responseJSON.d;
var dtCurrent = $e.attr("data-lastwrite");
if (dtCurrent) {
var curDate = new Date(dtCurrent);
var dtLastWrite = new Date(dt);
//refresh if modified date is higher than current date
if (dtLastWrite > curDate) {
$e.attr("src", getPathFromUrl($e.attr("src")) + "?d=" + new Date());//fool browser with date querystring to reload image
}
}
$e.attr("data-lastwrite", dt);
});
}).promise().done(function () {
window.setTimeout(CheckIfChanged, pollingInterval);
});
}
$(document).ready(function () {
window.setTimeout(CheckIfChanged, pollingInterval);
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<img class="img" src="/img/rick.png" alt="rick" />
If you are going to check whether files has changed on the server you have to make http request from the server for the file time, because there is no other way for your check the file time once page get loaded to the browser.
So that time check script will like
filetimecheck.php
<?php
echo filemtime(string $filename);
?>
Then you can check the file time using your Javascript. BTW I have put jQuery $.get for check the file time.
dusplayimage.php
<img id="badge" src="image.jpg"> />
<script>
var image_time = <?php echo filemtime(string $filename); ?>;
var timerdelay = 5000;
function imageloadFunction(){
$.get("filetimecheck.php", function(data, status){
console.log("Data: " + data + "\nStatus: " + status);
if(image_time < parseInt(data)) {
document.getElementById('yourimage').src = "image.jpg?random="+new Date().getTime();
}
});
setTimeout(imageloadFunction, timerdelay);
}
imageloadFunction();
</script>
You will be using extra call to the server to check the file time which you can't avoid however you can use the time delay to fine-tune the polling time.
Yes, you can customize this behavior. Even with virtually no change to your client code.
So, you will need a ServiceWorker (caniuse 96.59%).
ServiceWorker can proxy your http requests. Also, ServiceWorker has already built-in storage for the cache. If you have not worked with ServiceWorker, then you need to study it in detail.
The idea is the following:
When requesting a picture (in fact, any file), check the cache.
If there is no such picture in the cache, send a request and fill the cache storage with the date of the request and the file.
If the cache contains the required file, then send only the date and path of the file to the special API to the server.
The API returns either the file and modification date at once (if the file was updated), or the response that the file has not changed {"changed": false}.
Then, based on the response, the worker either writes a new file to the cache and resolves the request with the new file, or resolves the request with the old file from the cache.
Here is an example code (not working, but for understanding)
s-worker.js
self.addEventListener('fetch', (event) => {
if (event.request.method !== 'GET') return;
event.respondWith(
(async function () {
const cache = await caches.open('dynamic-v1');
const cachedResponse = await cache.match(event.request);
if (cachedResponse) {
// check if a file on the server has changed
const isChanged = await fetch('...');
if (isChanged) {
// give file, and in the background write to the cache
} else {
// return data
}
return cachedResponse;
} else {
// request data, send from the worker and write to the cache in the background
}
})()
);
});
In any case, look for "ways to cache statics using ServiceWorker" and change the examples for yourself.
WARNING this solution is like taking a hammer to crush a fly
You can use sockets.io to pull information to browser.
In this case you need to monitor image file changes on the server side, and then if change occur emit an event to indicate the file change.
On client (browser) side listen to the event and then then refresh image each time you get the event.
set your image source in a data-src property,
and use javascript to periodicaly set it to the src attribute of that image with a anchor (#) the anchor tag in the url isn't send to the server.
Your webserver (apache / nginx) should respond with a HTTP 304 if the image wasn't changed, or a 200 OK with the new image in the body, if it was
setInterval(function(){
l= document.getElementById('logo');
l.src = l.dataset.src+'#'+ new Date().getTime();
},1000);
<img id="logo" alt="awesome-logo" data-src="https://upload.wikimedia.org/wikipedia/commons/1/11/Test-Logo.svg" />
EDIT
Crhome ignores http cache-control headers, for subsequent image reloads.
but the fetch api woks as expected
fetch('https://upload.wikimedia.org/wikipedia/commons/1/11/Test-Logo.svg', { cache: "no-cache" }).then(console.log);
the no-cache instructs the browser to always revalidate with the server, and if the server responds with 304, use the local cached version.