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Saving changes in javascript file

I have a html code that creates an input form on the browser and a javascript file that creates an array.The javascript program takes the input value and add it to the array and after display it on browser.
window.alert("Add some text")
var x;
var arr=["text1","text2"]
function myFunction() {
x=document.getElementById('input').value;
x=x.toLowerCase();
var y=arr.indexOf(x);
if (y!=-1) {
window.alert("You have added this text before");
} else {
arr.push(x);
document.getElementById('demo').innerHTML=arr ;
}
}
The problem is that when I exit the file(the web page displayed on my browser) I lose the inputs.Let's say that I add "text3" and the program display text3,when I exit the browser I lose the input "text3".
What can I do to save the inputs and display them even if I exit the program and I enter again?
Can I make two javascript file one with the array(like a database) and one that takes the input and save it in the other javascript file,and if so how do I make it?

As javascript is client side you will never be able to store permanent data as the script will be loaded (reset) after any refresh. Are you aware of the html5 localstorage concept? Saving data from js to the browsers storage space.
Edit:
Quick start on localstorage - http://www.w3schools.com/html/html5_webstorage.asp

save to localstorage dynamic JQuery rows

I think I have a major fault in my webpage design. I need to save the content if I reboot the computer or close the webpage.
I do not have access to any type of a database server only MS Access. I was thinking of utilizing localstorage as the page will be constantly viewed from the same computer.
I found this example [link]Edit functionality using javascript and local storage however I am not sure if it will work.
Can someone look at my example and let me know if I can do this or if I need to abandon this and start over.
$(document).ready(function () {
var id = 0;
// Add button functionality
$("table.dynatable button.add").click(function () {
id++;
var master = $(this).parents("table.dynatable");
// Get a new row based on the prototype row
var prot = master.find(".prototype").clone(true);
prot.attr("class", "")
prot.find(".id").attr("value", id);
master.find("tbody").append(prot);
});
// Remove button functionality
$(document).on("click", "table.dynatable button.remove", function () {
$(this).parents("tr").remove();
});
});
http://jsfiddle.net/deaconf19/csL68/
Thanks

If you are running the web page from a web-server -- that is, your URL begins with http:// or https://, then yes, you can use localStorage to save data.
If you are running the file directly from your hard drive, that is, your url begins with file:, then you'll have trouble. Chrome won't let you use localStorage -- I don't remember if Firefox does.
(If you need to run this from your local hard drive and not a server, and you are running under Windows, you can turn the file into an HTA and save data to a regular file.)

Get Element available under Dev Tools -> Resources -> Frames

I'm trying to do this by using a Tampermonkey Script. However I'm open to new approaches...
What I want to do is extract some data (data-video), from a specific <div>. However this data is not available under the HTML code of the page, but it's available under Dev Tools -> Resources and then on Frames.
Anyone knows if it's possible to get that information available under DevTools? And how can I do that?
Comparative between the two pages can be found here: "Original HTML PAGE" and "HTML PAGE under DevTools"
On the first hyperlink the id=video-canvas cannot be seen, however it's on the <object type="application/x-shockwave-flash(...)

As you state in your question the data you're looking for is available in DevTools under the "Resources" tab in the "Frames" folder. What you are looking at there is the Source HTML, similar to View Source.
The code you want, is what is getting replaced. It appears the site is using the JW Player Plugin, which is replacing the <div id="video-canvas"> with the appropriate HTML for the device / browser detected to play the video. With all of my browsers on my Mac, they are being forced to use the Flash, even when it's disabled. When using my iPhone, which can't play flash , and inspecting the page it uses JW's own custom video element. It appears that it must be storing the file location in memory since it is not in the generated markup.
I am able to run through the console in the dev tools and access their JS class. It appears i can call jwplayer._tracker , which has an object b . Object b has an object AlWv3iHmEeOzwBIxOUCPzg This object seems to be consistent each time i check between different browsers, you can use the for loop inmy first example to get the correct value but tirmming it down to .b Following that object is e and in e is the object http://i.n.jwpltx.com/v1.... really long string that appears to contain a url, so it will need to parsed.
So to get the HTML string i ran
for ( var loc in jwplayer._tracker.b.AlWv3iHmEeOzwBIxOUCPzg.e){
loc
}
so if we put that in a function to parse the string and return a value
function getSubURL(){
var initURL;
for ( var loc in jwplayer._tracker.b.AlWv3iHmEeOzwBIxOUCPzg.e){
initURL = loc;
}
//look for 'mp4:' this is in front of the file path
var start = initURL.indexOf("mp4%3A");
//look for the .mp4 for the end of the file name
var stop = initURL.indexOf(".mp4");
//grab the string between
//start+6 to remove characters used to find it
//and stop+4 to include characters used to find it
var subPath = (initURL.substring((start+6),(stop+4))).split("%2F").join("/");
return subPath;
}
//and run it
getSubURL();
it will return ciencia/astronomia/fimsol.mp4
you can run this from your console, but I am unaware of how you can use this in Tamper Monkey, but i think it gets ya a lot closer to what you wanted.

This is the approach I've used to solve my problem... I couldn't grab the code I want under Dev Tools, but I find a way to get the data from jwplayer with the function getPlaylistItem. And this is how I get the url filename of each video:
function getFilename(filename) {
var filename;
if(jwplayer().getPlaylistItem){
filename = jwplayer().getPlaylistItem()['file'];
}
else{
return filename;
}
filename = filename.substring(filename.indexOf("/mp4:") + 5);
return filename;
}

Different external .js files with same variable names

I'm making a websites that displays noise measurement data from different locations. The data for each location is captured on a sound level meter device and it is then read with a windows-based application. The application then uploads data on a web server as a .js file with an array variable in it. This .js files are refreshed every 5 minutes.
I first created a javascript application that displays live data for a single measuring unit. But now I need to display data on a map for all the locations. The problem is that the windows application on each location makes a file with the same name and same variables only on another location. I'm having some trouble with reading the correct data.
This is what I did so far:
function removejscssfile(filename, filetype){
var targetelement=(filetype=="js")? "script" : (filetype=="css")? "link" : "none" //determine element type to create nodelist from
var targetattr=(filetype=="js")? "src" : (filetype=="css")? "href" : "none" //determine corresponding attribute to test for
var allsuspects=document.getElementsByTagName(targetelement)
for (var i=allsuspects.length; i>=0; i--){ //search backwards within nodelist for matching elements to remove
if (allsuspects[i] && allsuspects[i].getAttribute(targetattr)!=null && allsuspects[i].getAttribute(targetattr).indexOf(filename)!=-1)
allsuspects[i].parentNode.removeChild(allsuspects[i]) //remove element by calling parentNode.removeChild()
}
}
function updateData(){
var numberOfNoiseSniffers = noiseSniffers.length-1;
var j = 0;
for (i=0;i<=numberOfNoiseSniffers;i++) {
file = '../'+ noiseSniffers[i] + "/" + "CurrentMeasurement.js";
$.include(file,function(){
laeq[j] = currentMeas[1][1];
lastUpdate[j] = currentMeas[0][1];
if (j==numberOfNoiseSniffers){
updateMarkers();
}
removejscssfile(file[0], "js");
j++;
});
}
t=setTimeout(function() { updateData() }, 300000);
}
$(function (){
map = new google.maps.Map(document.getElementById("gMap"), myOptions);
//noiseSniffers is an array where I have save all the folder names of different measurement locations
var numberOfNoiseSniffers = noiseSniffers.length-1;
var j = 0;
for (i=0;i<=numberOfNoiseSniffers;i++) {
var file = '../'+ noiseSniffers[i] + "/" + "CurrentMeasurement.js";
//I am using include plugin for jquery to include files because it has a callback for when a file is actually loaded
$.include(file,function(){
//a set of global arrays that keep the data from the loaded file and this data is then displayed in google maps markers
laeq[j] = currentMeas[1][1];
lastUpdate[j] = currentMeas[0][2];
latitude[j] = systemstats[12][5];
longitude[j] = systemstats[11][6];
//checking to see if I am in the process of including the last file
if (j==numberOfNoiseSniffers){
//a function that creates google maps markers
createMarkers();
}
//after that I remove the files that were just included and read
removejscssfile(file, "js");
j++;
});
}
setTimeout(function() { updateData() }, 300000);
});
I got the function for removing my .js file here: Dynamically removing an external JavaScript or CSS file.
And this is the jquery plugin for loading the .js file: Include File On Demand.
The initial load usually works (sometimes it happens that only one or no markers get loaded. But the update function mostly returns the same data for both locations.
So what I want to know is, how can I firstly make my code working and how to optimize it. I posted just the main parts of the javascript code, but I can provide all the code if it is needed. Thanks for any help.

I think you need some sort of JSONP-like solution.
Basically load data on the server side, then wrap it in a method call before returning it to client side. Your response should look something like this:
var location_data = [1,2,3,4]
updateLocation('location_id', location_data)
Now you define an updateLocation() function in your client side script. Now, every time you need new data, you create new 'script' tag with src pointing to your server side. When the response is loaded, your updateLocation() will be invoked with correct params.
I hope this is clear enough

You can maybe try some form of namespacing

i exactly dont understood your problem, but you may try this
//put your code inside an anonymous function and execute it immediately
(function(){
//your javascript codes
//create variable with same names here
//
})();

How to use javascript to get information from the content of another page (same domain)?

Let's say I have a web page (/index.html) that contains the following
<li>
<div>item1</div>
details
</li>
and I would like to have some javascript on /index.html to load that
/details/item1.html page and extract some information from that page.
The page /details/item1.html might contain things like
<div id="some_id">
picture
map
</div>
My task is to write a greasemonkey script, so changing anything serverside is not an option.
To summarize, javascript is running on /index.html and I would
like to have the javascript code to add some information on /index.html
extracted from both /index.html and /details/item1.html.
My question is how to fetch information from /details/item1.html.
I currently have written code to extract the link (e.g. /details/item1.html)
and pass this on to a method that should extract the wanted information (at first
just .innerHTML from the some_id div is ok, I can process futher later).
The following is my current attempt, but it does not work. Any suggestions?
function get_information(link)
{
var obj = document.createElement('object');
obj.data = link;
document.getElementsByTagName('body')[0].appendChild(obj)
var some_id = document.getElementById('some_id');
if (! some_id) {
alert("some_id == NULL");
return "";
}
return some_id.innerHTML;
}

First:
function get_information(link, callback) {
var xhr = new XMLHttpRequest();
xhr.open("GET", link, true);
xhr.onreadystatechange = function() {
if (xhr.readyState === 4) {
callback(xhr.responseText);
}
};
xhr.send(null);
}
then
get_information("/details/item1.html", function(text) {
var div = document.createElement("div");
div.innerHTML = text;
// Do something with the div here, like inserting it into the page
});
I have not tested any of this - off the top of my head. YMMV

As only one page exists in the client (browser) at a time and all other (virtual/possible) pages are on the server, how will you get information from another page using JavaScript as you will have to interact with the server at some point to retrieve the second page?
If you can, integrate some AJAX-request to load the second page (and parse it), but if that's not an option, I'd say you'll have to load all pages that you want to extract information from at the same time, hide the bits you don't want to show (in hidden DIVs?) and then get your index (or whoever controls the view) to retrieve the needed information from there ... even though that sounds pretty creepy ;)

You can load the page in a hidden iframe and use normal DOM manipulation to extract the results, or get the text of the page via AJAX, grab the part between <body...>...</body>¨ and temporarily inject it into a div. (The second might fail for some exotic elements like ins.) I would expect Greasemonkey to have more powerful functions than normal Javascript for stuff like that, though - it might be worth to thumb through the documentation.