Replicating preloaded HTML /DOM method results in an array using AJAX/PHP - php

Question

I have a function that creates an array that contains the return value from the HTML DOM method : window.document.getElementById()
function makearray1(){
var array1=[1,window.document.getElementById('divID'),['a','b'],[1,2]];
}
then I pass the array into another function
use(array1)
function use(xxx){
xxx[1].innerHTML=xxx[2][0];
}
and 'a' is written in the appropriate div
later I decided to put the array in a form and post it to a txt file on the server using php and:
JSON.stringify(array)
So now I use AJAX to call the data from the txt file after the rest of the page has loaded etc... and the original function used to make the array is not included at all.
so my php is basically this:
$a1='use(';
$data1 =file_get_contents("text_file.txt") ;
$a2=')';
echo $a1.$data1.$a2;
and the response text:
var n= XMLHttpRequestObject.responseText;
eval(n);
which pretty much means this:
use(text_file)
function use(xxx){
xxx[1].innerHTML=xxx[2][0];
}
the problem is that the array in the text file looks like this:
[1,null,['a','b'],[1,2]]
instead of:
[1,window.document.getElementById('divID'),['a','b'],[1,2]]
My question: Is there any way that I can do the equivalent of what I'm trying to do here, which is immediately replicate the return value of the HTML/DOM method in an array using AJAX/php?
To clarify: this is a simple example. I actually have a huge, multidimensional array that already has established pointers, or prefetched DOM nodes in it. Now I'm trying to replicate the array when a text version is loaded using ajax. I'm looking for a recursive approach to changing all of the null assignments with something that will immediately fetch the appropriate DOM node. Most likely I will need to do it with the response text, but was hoping I could do it with the php portion.

Answer 1

You're trying to stringify a reference to a javascript object in the memory of whatever computer is evaluating getElementById first, and that has no chance to represent something on the end client's computer.
Send the id instead:
function makearray1(){
array1=[1,'divID',['a','b'],[1,2]];
}
then, in the client:
function use(xxx){
window.document.getElementById(xxx[1]).innerHTML=xxx[2][0];
}
If you really want to eval it at the end, you can use this, I guess
function makearray1(){
array1=[1,"window.document.getElementById(\"divID\")",['a','b'],[1,2]];
}
I've no idea why you would want to do that though

Answer 2

Assuming the dom element exists in the second page, it should look something like this.
JS:
function packDomData(){
return {
"MySpecificYetBriefProperty0":1,
"DomID":"divID",
"MySpecificYetBriefProperty1":['a','b'],
"MySpecificYetBriefProperty2":[1,2]
};
}
function useDomData(domData){
document.getElementByID(domData.DomID).innerHTML=domData.MySpecificYetBriefProperty1[0];
}
PHP:
//Make sure the contents of this file is the json from packDomData. use json_encode in php or JSON.stringify in js
echo file_get_contents("text_file.txt");
var myData = JSON.parse(XMLHttpRequestObject.responseText);
useDomData(myData);
I used to code like you. Here are some tips that have helped turn my coding horror into a fun job:
Use objects with descriptive properties instead of arrays whenever you aren't actually looping through the array - I promise it will save you and others headache! "DomID" is much more flexible than 1, and if you change the order in the array, javascript gods help you that array is everywhere - including however many random text files on your server!
Also use descriptive names for functions
Always return a value from a function instead of using globals whenever possible, even where the result is then used as a nasty global. Trust me.
Never put javascript function names in an ajax call. Use JSON instead and keep the functions and other script in the javascript file where it belongs.
Mysql will save your life!!
Disclaimer - I didn't run this code but it should basically work when you get everything hooked up right.