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Pass Javascript variable to another page via PHP Post

I am having two php pages:
page 1:
<form class="form-horizontal" role="form" method="post" action="Page2.php">
<button id="place-order" class="btn btn-lg btn-success">Place Order</button>
<div id="ajax-loader" style="display:none;"><img src="images/ajax-loader.gif" /></div>
</form>
<script>
var id = Math.random();
$(document).ready(function() {
$('#place-order').on('click', function() {
$(this).hide();
$('#ajax-loader').show();
});
});
</script>
As on form, it redirects to Page2.php, I want to pass the Javascript variable "id" from Page1 to receive it in Page2.
I have tried using cookies, but need an alternative approach.
I am not understanding the transistion from PHP to JS and vice-versa. Help is appreciated.
Thanks in advance

Dear you can do it very easily with ajax. Ajax has data attribute which helps you pass your data from javascript to another page.
This link will help you a lot
https://api.jquery.com/jquery.ajax/

You can use session storage or cookies.
Example for session storage:
// First web page:
sessionStorage.setItem("myVariable", "myValue");
// Second web page:
var favoriteMovie = sessionStorage.getItem('myVariable');

You could use a query string to pass the value to the next page.
Add an ID to the form
<form class="form-horizontal" role="form" method="post" action="Page2.php" id="order-form">
Update the action of the form to add this query string from our JS variable
var id = Math.random();
$('#order-form').attr('action', 'Page2.php?id=' + id);
Get this variable in PHP (obviously you might wanna do more checks on it)
<? $id = $_GET['id'] ?>
We can now use $id anywhere in our PHP and we'll be using the ID generated from JS. Neat, right? What if we want it in JS again though? Simply add another script tag and echo it there!
<script type="text/javascript">
var id = <? echo $id ?>;
</script>
EDIT: Updated to add a little about how it works as you said you're not too sure about the transition between PHP and JS.
PHP runs on the server. It doesn't know much about the browser, and certainly doesn't know about JS. It runs everything and finishes executing before the web page is displayed. We can pass PHP variables to JS by creating script tags and creating a new javascript variable, echoing the PHP value.
JS (JavaScript) runs in the browser. It doesn't know about anything that happens on the server; all it knows about is the HTML file it is running in (hit CTRL+U to see raw HTML). As JS runs at a completely separate time to PHP there is no easy way to transfer variables (e.g. $phpVar = myJSVar). So, we have to use server methods like POST or GET.
We can create a GET or POST request in 2 main ways:
Using a form
Using an AJAX request
Forms work in the way I've outlined, or you can create a hidden field, set the value you want and then check for that. This involves redirecting to another page.
AJAX (Asynchronous Javascript And Xml) works slightly differently in that the user doesn't have to leave the page for the request to take place. I'll leave it to you to research how to actually program it (jQuery has a nice easy API for it!), but it basically works as a background request - an example would be displaying a loading spinner whilst loading order details from another page.
Hope this helps, let me know if something's not clear!

How to get a DIV element from an external webpage in HTML file?

Apologies in advance if this question has been asked earlier. I did find some similar questions on web but I couldn't figure out the answer still. You can say I have never dealt with anything beyond basic HTML. So any help would be appreciated.
I have a HTML file (Say text.html) only for personal use. In the file, there will be an input box for entering text and a submit button. I want that if I clicks on submit, it opens a particular hyperlink from an external webpage based on the input text. I guess it's like "I am feeling Lucky" of Google.
Example: If the user enters "Test" and clicks on Submit, it should open the second result from the page "https://www.google.com/search?q=test"
Here is my HTML:
<!DOCTYPE html>
<html>
<body style="background-color:beige">
<h1 style="text-align:center"><font size="14">Test</font></h1>
<style type="text/css">
</style>
<form id="form">
<div align="center" style="vertical-align:bottom">
<input type="text"
value="Test"
id="input"
style="height:50px;width:200px;font-size:14pt;">
</div>
</form>
<TABLE BORDER="0">
<TD><button class="button" id="button01">SUBMIT</button></TD>
<script type="text/javascript" src="http://code.jquery.com/jquery-1.11.0.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$('#button01').click(function(e) {
var inputvalue = $("#input").val();
window.open("https://www.google.com/search?q="+inputvalue);
});
</script>
Also, here is the example of the div element from the page on which the hyperlink I want to open is on:
<div id="XYZ" class="contentEditValue" style="float:left;width:180px;">
2nd Result
</div>
I have read that it can be achieved with PHP or Jquery and all but they are not something I have ever worked on. Thank you very much in advance for any help!
Appreciate any other alternatives as well.

You shouldn't be able to do that because of security. If that (reading content from iframes, other browser windows...) would be possible, an attacker could add JS keylogger to your internet banking login or read your messages on Facebook. CORS (https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS) is used to block these requests and if the website doesn't say explicitly that you are allowed to do something with its content, most browsers won't allow you that.

You have are missing a }); to close the ready() function
<script type="text/javascript">
$(document).ready(function(){
$('#button01').click(function(e) {
var inputvalue = $("#input").val();
window.open("https://www.google.com/search?q="+inputvalue);
});
});
</script>

Here's a basic example of how to do this in PHP.
Taking JavaScript/JQuery out of the picture, let's just say you have a basic form:
<form>
<input type="text" value="Test" name="input">
<input type="submit">
</form>
Without specifying action or method attributes on the <form> tag, the form will make an HTTP GET request to the URL of the page it is on, so for this example the PHP code will be on the same page as the form. Here's a more detailed description of sending form data if you're interested.
Now that you have a way to pass the input to the PHP script*, there are three basic parts to this problem.
Make a request to the page you want with a query string including your input
http_build_query is an easy way to construct a properly encoded query string to use with your request. For this example we'll use file_get_contents to make the request. There are other ways to do it, including cURL, but let's keep it simple.
$query = http_build_query(['q' => $_GET['input']]);
$page = file_get_contents('http://www.example.com/?' . $query);
I'm not using Google for this example because it's a bit more complicated to find the right links in the response and follow them. (Partially because they don't really want you to do it that way.)
Find the link you want in the response
Don't try to find the link in the response with regex. You'll have problems with it, come back to Stack Overflow to try to solve them, and people will tell you that you shouldn't be using regex, so just skip that part and use a DOM parser.
$doc = new DomDocument;
$doc->loadHTML($page);
$links = $doc->getElementsByTagName('a');
$url = $links[0]->getAttribute('href');
I used getElementsByTagName() to find links, but if the page is more complex an xpath query will work better. Also, I used the first link ($links[0]) because example.com only has one link. $links[1] would get you the second link if it existed.
Follow the link
header("Location: $url");
exit;
If everything goes well, you'll end up where you want to be. But there are a lot of things that can go wrong. If you're requesting a resource that you have no control over, it can change at any time without any advance warning to you, so your code that finds the link may stop working. You may get blocked from making requests. Scraping links from sites like this violates the terms of service on many sites, so check that out beforehand. You may find that the site offers a web API, which should be a much better way to access its content than this.
*You don't really need a form for this; you can just pass the input parameter in the URL to your page.

Retrieve variable name from an HTML site

I am trying to retrieve simple javascript variable (which is written to a File Systems Object) from a website which is served by an apache host on my ubuntu laptop.
So I have the function that writes the variable set up as follows:
<script type ="text/javascript">
function WriteToFile(passForm) {
set fso = CreateObject("Scripting.FileSystemObject");
set s = fso.CreateTextFile("/home/lex/Downloads/goal.txt", true);
s.writeline(document.passForm);
s.Close();
}
</script>
and the section that takes the user input from the html website is
<div id="bot-right">
<form onsubmit="WriteToFile(this['goal'].value)">
<a align = "left"> <b><Strong>Enter a Goal name</Strong></b></a><br>
<input type="text" name="goal"> <br>
<input type="submit" value="Send Zeus">
<br>
</form>
</div>
For some reason, when I type in variable names to the form on the website, the file goal.txt gets created in the directory, /home/lex/Downloads/, but nothing gets written to it.
I also noticed that when I delete the goal.txt file and rewrite the variable from the html website, the file doesn't always get created.
I am not a JavaScript person and I am at a loss as to what I may need to fix this.
My intention is to get the variable written to the text file and have a processing c++ file process the variable.
Would someone be kind enough to lend an insight?
Thanks!

one way to do it is just calling the function without parameters and just getting the input value like this:
adding and id or a class to your input to get that specific value:
document.getElementById('goal').value
document.getElementByClass('goal').value
Or getting the value by name:
document.querySelector('[name="goal"]').value;
EDIT1
You could add a console.log to check if the value is beign passed correctly like this:
var inputValue = document.querySelector('[name="goal"]').value;
console.log(inputValue);
And if the value is being passed then the problem is your writeline or in the creation of the document
EDIT2
I just tested it and retrieving the value works just fine, so the problem must be in your document writing method, please check this documentation it can help you and i think is a better solution:
http://www.html5rocks.com/en/tutorials/file/filesystem/

How to get information from Javascript to MySQL database using PHP?

(NEWBIE ALERT)
Hello! I am working on developing a database that stores information that people enter onto these online surveys. I don't have experience with Javascript, but I have worked with PHP and MySQL before. I am currently stuck on how to store the data to the database. Here are a few things about the code:
The person that created the online surveys had the online surveys written in Javascript (saved as HTML files)
Each survey is written in a separate file
Each survey has multiple data to be stored
Every time the user hits the next button, it goes to another page of the survey
I've worked on a project similar to this before, but my forms were only a page, so whenever the user clicks the "Submit" button, I had it go to another webpage written in a separate PHP file (kind of like a "results" page).
WHAT I DON'T UNDERSTAND/NEED HELP ON:
How do I make this so that when the user hits the "Next" button, it not only goes to the next page (what it's doing right now), but also sends the info to be stored in the database?
These surveys should be filled by people on their own computers so the surveys are written in JS (client-side). The storing part should be written in PHP (server-side) and MySQL, correct? Does this mean that I have to create a separate PHP file to create the code for transferring the data to the database or can it all be done in the same file? (I would think that I would need to create a separate file, one for each survey.)
Here's a general structure of how the HTML file:
<!DOCTYPE html>
<html>
<head><link rel="stylesheet" type="text/css" href="survey.css">
<script>
function Q2(){
document.getElementById("Q").innerHTML = "does something...<button type='button' onclick='Q3()'>Next</button>";
function Q3(){
document.getElementById("Q").innerHTML = "does something...<button type='button' onclick='Q4()'>Next</button>";
function Q4(){
document.getElementById("Q").innerHTML = "does something...<button type='button' onclick='Q5()'>Next</button>";
//keeps going until the last question
</script>
</head>
<body>
<h1>Meeting 1</h1>
<p id="Q">Some text...<br><input type="text" name="tweet" style='height: 50px;width: 500px;'><br><br>
<button type="button" onclick="Q2()">Next</button>
</p>
</body>
</html>
I've done a bit of research and looked at a few textbooks. I think AJAX may be something that I need to use? But I'm not too sure. If possible, could someone explain to me what I should be doing? I would like to not only be able to find a solution for this, but understand it as well.
Thank you in advance!!

For sending data to a PHP page using JavaScript, I'd recommend using the jQuery framework, where you can do it in as simple a code as this:
function Q2(){
var tweet = $("input[name='tweet']").val();
$.post("your_receiving_page.php", { data : tweet }, function(response){ //POST to PHP page where $_POST["data"] is the tweet variable
//deal with PHP output here
console.log(response);
if(response=="success"){
//javascript code to go to next page etc.
}
}
}
That way, you make a PHP file called "your_receiving_page.php" (or whatever) and handle the posted data like so:
<?php
$tweet = $_POST["data"];
//do stuff with $tweet, e.g. put it in a database
//...
//then end the code with "success", which is what you're looking for in the JavaScript as a successful callback
exit("success");

How to get url for D3.json dynamically using input tag type=file?

Am using D3.js to input a json file and graphically plot it.
Here's my js required:
function loadJSON(url) {
d3.json("url", function(data) {
dataProcessor(data);
});
}
Here's my html required:
<body>
<div><h1>Chart 101</h1></div>
<input id="source" type="file">
<button id="clickHere" onclick="loadJSON()">CLick here</button>
<script src="../js/d3.v3.min.js"></script>
<script src="../js/ChartFactory.js"></script>
</body>
Bascially d3.json requires the url of the file selected.
Check here
But since mozilla doesnt allow the path to be visible using the "inputId.value",i cant seem to move forward with this.
Is there any solution or work around for this?

It is not possible to get the file full path on client machine using browser and javascript.
you have to upload file to server using form and then get the file.