Javascript Variables to PHP Script

Question

I could see that this question was being asked a lot of times and I did extensive research on what methods could be used to transfer a couple of Javascript variables to a PHP script.

1. Post data in a form as hidden values
2. Post to URL, i.e. '/txt.php?h=' + var
3. Use a cookie

I'm trying write a piece of code that will let you download what you've written in Wrrrite.com - I'm the developer of this website. (I also did a client-side approach of putting the variables into the URI and setting a header to download stuff)

None of this is working. Either there's a character that's causing an error, or there are html elements.

Is there something I can code to guarantee a 1:1 transfer of the work/variables?

Datatype: HTML + various different Characters "!§!' etc. Output: .txt File, perferably a 1:1 translation of what was being written on the form

Answer 1

You should maybe use a Base64 encoding of your data, before sending it. Have a look at MDN for the JavaScript part and here for the PHP decoding. This should prevent special characters from breaking your code.

Answer 2

Hope it helps

//PHP

 if(isset($_REQUST['submit']))
{
  $download=$_REQUEST['download'];
// from database get value of all the downloadable items
// and check if the input is in that array then to the suitable thing. 
}
//HTML
<form method="post" action=''>
Type :<input type="text" id="txtField" name="txtField" />
<input type="hidden" name='download' />
<input type="submit" name="submit" onclick="return onSubmit() " />
</form>

//Javascript

<script type="text/javascript">
function onSubmit()
{
if(document.getElementById("txtField").value != '')
{
  document.getElementById("download").value=document.getElementById("txtField").value;
return true;
}
else
{
 alert("Please enter item to download");
return false;
}
}

Answer 3

Here's the Cookie Approach, which doesn't work http://pastebin.com/SKNtxLi5

That just slaps values together without any consideration for the data format used in cookies.

Quirks Mode has a decent guide to cookies with JS if you want to fix that.

However… the point of cookies is that the data persists. It isn't a sensible transform for one shot messages.