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How to pass an array from javascript to php

So i've been asked to remake some registration forms. The way its supposed to work is, that an interpreter chooses X amount of languages in the first select box. Then based on the selections of languages, the user must specify from which languages they can translate from/to.
I want to store this data in a key/value array, with the key being "LanguageFrom" and Value being another array, of "LanguagesTo". This is how i have solved this:
function btnTest() {
var fromArray = $('.freelancerLanguagesFrom').map(function() {
return $(this).val();
}).get();
var toArray = $('.freelancerLanguagesTo').map(function() {
return $(this).val();
}).get();
var tempArray = {};
tempArray[fromArray] = toArray;
}
This method is being called with an "onclick" function in the html part. The user should specify which languages he can translate to for each of the chosen languages in the first box,
I am aware that this probably isn't the ideal approach, but im still an inexperienced developer, and i'd love to hear your take on another approach.
Now comes my problem:
1) How do i make it so the array wont overwrite the existing array with each button click, and instead just add to the array?
2) How do i process this array on the server side (php), so that i can store the values in my database?
3) Is it possible to skip the flow where the user has to press the save(gem) button after each language he has chosen?
edit: Question 1 and 3 are now solved, my only problem is accessing the array i made in js, on the php side

1) tempArray exists only in the scope of the btnTest() function. Declare it outside (in the global scope), initialize it as {} and don't reset it every time you click the button. The way you get the fromArray variable may require some tweaking depending on whether the "from" list can accept a multiple selection or not.
2) Ajax may help. Create a php endpoint to receive the request and call it using ajax. You can work on the array using JSON. Send your data using JSON.stringify(tempArray) and read it using json_decode() in your php script, or simply set the request headers as "application/json" to have it done automatically for you.
3) I personally wouldn't automate this process. Let's say I have 4 languages, Italian, English, French and Chinese.
I have selected a desirable state of languages I can handle:
Italian -> English, French
But I also know how to translate French in Italian so I click, in the from list, French, and I get
French -> English
Which is an undesirable state, for me, because I don't know how to do that. Especially if I were to select many languages, I'd get, inbetween 2 states I want to save, an indefinite amount of states I don't want to save.
If you still want to do so, you need to move the even listener from the button to the list(s), with the onchange event.
I'd also suggest you do your event binding trough jQuery, if you aren't already.
Hope this helped.

How can I handle a potentially pre-filled form with Jade?

I have this huge form that only gets pre-filled data if data already exists in a database. Otherwise, none of the text boxes should have the value parameter in them. I thought it would just ignore the value parameters if the variable I get data from does not exist. But instead, I get an error.
How to I handle this case? Will I have to do an if check before each text box in Jade like the following?
if (typeof(prefilled_data) !== 'undefined')
input.form-control#prevalence(type="text", name="prevalence")
else
input.form-control#prevalence(type="text", name="prevalence", value=prefilled_data.tb_burden_estimates.prevalence)
While I don't mind doing this (Sublime Text will help with all the copy-pasting), there are quite a few form fields, so it might get ugly. Is there a way to consolidate this into one check somewhere?

you seemed to be suggesting that the if statement's were going to be bulky/make the code hard to read if they were there.. my suggestion would be to programmatically create the inputs, there by reducing the if statements to a more manageable number and answering your question about being able to "consolidate this into one check somewhere"
EDIT
If you are looking to access data in js.. I have been known to use something like:
script(type='text/javascript').
window.prefilled_data = !{ JSON.stringify(prefilled_data) };
This will allow you then to access the global window.prefilled_data variable to get front end version of your data

you can do this:
- if (typeof(prefilled_data) === 'undefined'){
- prefilled_data = '';
- }
input.form-control#prevalence(type="text", value=#{prefilled_data})
if prefilled_data is undefined you just set a '' value

How can I get Javascript to execute as a table is being built?

I have a table being built in HTML (using ASP), and it's stepping through a recordset. As it steps through the recordset, it creates a new row for the html table and fills it with data.
The problem I'm having is that it's using numbers that can be 10 or 11 digits long, and I want to format it with commas. I have a formatNumbers function that works excellently. However, basically what I need to do is this:
<td><script>formatNumber(<% = RS("total_rolled_lineal_ft")%>,0,0,true);</script></td>
I'm getting an Object Expected error. If we take a line from the executed HTML, here's what it looks like:
<td><script>formatNumber(10843537,0,0,true);</script></td>
Any clue what's causing my error, or, if I'm doing it completely wrong, how to fix it?
Also, formatNumber returns a string, in this case 10,843,537.

Thanks to #nnnnnn, I ended up using VB's FormatNumber() and came up with this
<% = FormatNumber(RS("total_rolled_lineal_ft"),0,true,true,true)%>, which works excellently.

I have never used straight ASP so maybe I am missing something in this answer.
Technically you can not execute Javascript while the ui is rendering, browsers tend to be a single threaded affair and will do one thing or the other.
But I would suggest that instead of binding the table directly to a record set you transform the record set into a ViewModel type class in the code behind.
You would then perform this conversion as you are building your ViewModel.

Whats the best way to resolve name conflicts in javascript?

I recently wrote some javascript code that filled a drop down list based on some XML, pretty simple stuff. The problem was I had to write similar code to do almost the same thing on a different page.
Because the code was almost identical I named most of the functions the same, thinking that they would never be included in the same page. However, naming conflicts arose because both javascript files were eventually included in the same HTML page.
When I had to go back and change the names I simply added first_ or second_ to the method's names. This was a pain and it doesn't seem very elegant to me. I was wondering if there is a better way to resolve name conflicts in javascript?

Try the JavaScript module pattern (or namespaces) used in various libraries.
Try to be DRY (don't repeat yourself) so you can avoid name collisions. If the code is almost the same you better avoid code duplication by creating a function which can handle both cases. The function can take two parameters: which dropdown to populate and with what data. This helps maintainability as well.
update: I assume that you take the XML from an AJAX request. In this case you can create on-the-fly anonymous functions with the appropriate parameters for callback inside a loop.

I would look at how I could merge the two pieces of code (functions?) into a single function. If you need to populate a list box, then pass the list box id into the function, so you are not hard-coded to operate on one single control only...
I did this on my rocket business's web site where I sold rocket motors with different delay values, but in essence, they were the same product, just a different delay value.
Perhaps this might try and explain what I'm trying to say... I use this if an image file happens to be missing, it will display a "no image" image in place of the real image.
function goBlank(image)
{
if(image) {
var imgobj = document[image];
imgobj.src="/images/blank.png";
}
}
In this case, you call it with:
<img src="/images/aerotech.png" name="header" onError="goBlank('header');">
If you need more example with things like list boxes used, let me know. Perhaps even post some sample code of yours.

Another option (if possible) is to carefully tie the code to the element itself.
e.g.
<input type="text" name="foo" id="foo" value="World" onchange="this.stuff('Hello ' + this.value);"/>
<script>
document.getElementById('foo').stuff = function(msg){
//do whatever you want here...
alert('You passed me: ' + msg);
};
</script>

Need help with an AJAX workflow

Sorry I couldn't be more descriptive with the title, I will elaborate fully below:
I have a web application that I want to implement some AJAX functionality into. Currently, it is running ASP.NET 3.5 with VB.NET codebehind. My current "problem" is I want to dynamically be able to populate a DIV when a user clicks an item on a list. The list item currently contains a HttpUtility.UrlEncode() (ASP.NET) string of the content that should appear in the DIV.
Example:
<li onclick="setFAQ('The+maximum+number+of+digits+a+patient+account+number+can+contain+is+ten+(10).');">
What is the maximum number of digits a patient account number can contain?</li>
I can decode the string partially with the JavaScript function unescape() but it does not fully decode the string. I would much rather pass the JavaScript function the faq ID then somehow pull the information from the database where it originates.
I am 99% sure it is impossible to call an ASP function from within a JavaScript function, so I am kind of stumped. I am kind of new to AJAX/ASP.NET so this is a learning experience for me.

First of all, if you're pulling the questions from the db on page load you most likely have all the answers too, so just keep going with your current approach by jamming the answers into the page as your code sample is doing. Unless your FAQ list has thousands and thousands of questions, doing it the "AJAX way" by hitting the db on each click of the list item doesn't give you much here IMO. If it does have that many questions then a straight list is the wrong way to go anyway.
Secondly, two things to keep in mind re your approach:
you're placing html inside an html attribute
the attribute is specifying a javascript function to call
So you need to make sure your "answer" escapes both html and is valid js. By valid js I mean it can't have new lines and must escape quotes properly. For example, the following html - although valid html - won't fire the onclick and you'd just get a js syntax error:
<li onclick="setFAQ('This line's
multi line and has a single quote in it!')"
To account for these I would say HttpUtility.HtmlAttributeEncode in tandem with System.Web.Script.Serialization.JavaScriptSerializer is more appropriate to the markup you've shown.
JavaScriptSerializer json = new JavaScriptSerializer();
string answerString = "This line's\nmulti line and has a single quote in it!";
string onClickJS = String.Format("setFAQ({0})", json.Serialize(answerString));
string onClickAttr = HttpUtility.HtmlAttributeEncode(onClickJs);
Even better, use .NET's ListItem object and lose HtmlAttributeEncode altogether:
ListItem faqItem = new ListItem(questionString);
faqItem.Attributes.Add("onclick", String.Format("setFAQ({0})", json.Serialize(answerString)));
The html portion is escaped automatically for you, plus it's a lot cleaner.
As for your javascript, you don't have to decode anything in setFAQ(). Just take its argument and put it in into you "answer" div:
function setFAQ(answer) {
document.getElementById('answer').innerHTML = answer
}

I think just using HttpUtility.HtmlEncode may solve your problem. I'm not sure I follow completely though : \