Parsing javascript variable from source code

Question

I need some javascript variables to be parsed in order to be updated onto an SQL database.

1) How would I parse this lines directly from the source code for example:

//our variables
var y = "bloblo";
var x = "blabla";
var z = "bleble";

(this block above would be somewhere in the source code of the page, and my objective is to retrieve it, and store it in some php variables) What would be the most appropriate way to do it?

2) Is there a way to directly access the source code of a website in order to use this parser and retrieve/save the data?

Can I use a callback function on a random webpage source ?

Raphael St
– Raphael St

2014-05-24 09:18:18 +00:00
Commented May 24, 2014 at 9:18 — Raphael St
– Raphael St, Commented May 24, 2014 at 9:18

lovasoa · Accepted Answer · 2014-05-25 15:13:46Z

1

This function does a basic parsing of a JS source to find variable definitions:

function parse_js_vars($source) {
    $res = array();
    $matches = array();
    $rx = "/(?:var)?\s+([\$A-Za-z_][$\w]*)\s*=\s*['\"]?([^'\";]*)[\"']?\s*(?:^|;)/";
    preg_match_all($rx, $source, $matches);
    foreach ($matches[1] as $n => $name) {
        $res[$name] = $matches[2][$n];
    }
    return $res;
}

Example:

parse_js_vars("var a=5;var b='hello';");

returns

array(
  "a" => "5"
  "b" => "hello"
)

answered May 25, 2014 at 15:13

lovasoa

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Raphael St Over a year ago

What is "[$\w]*" for? That I don't understand. Thanks for the regexp anyway.

lovasoa Over a year ago

[$\w] matches all letters, numbers, underscores and $ characters. This is to match every character that can be part of a variable name (but not the first character, that cannot be a number).

Raphael St Over a year ago

Isn't it alread done by "[\$A-Za-z_]" ?? Plus, shouldn't the short cut '\w' be outside of a class definition "[]"

Ilia Ross · Accepted Answer · 2014-05-24 09:33:12Z

0

Perform AJAX call using jQuery, for example:

$.ajax({
  type: "POST",
  url: "example.php",
  data: { y: y, x: x, z: z }
})
  .done(function( msg ) {
    // Perform changes on your page after AJAX request succeed.
    alert( "Data Saved: " + msg );
  });

You PHP server part, will be able to parse then:

$y = filter_input(INPUT_POST, 'y');
$x = filter_input(INPUT_POST, 'x');
$z = filter_input(INPUT_POST, 'z');

answered May 24, 2014 at 9:33

Ilia Ross

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Raphael St Over a year ago

I was actually looking for away to avoid this situation cause ajax is not cross domain, and what I need is to get the data from the source of a site that I don't own.

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