Parse JavaScript with jsoup

Question

In an HTML page, I want to pick the value of a javascript variable.
Below is the snippet of HTML page:

<input id="hidval" value="" type="hidden"> 
<form method="post" style="padding: 0px;margin: 0px;" name="profile" autocomplete="off">
<input name="pqRjnA" id="pqRjnA" value="" type="hidden">
<script type="text/javascript">
    key="pqRjnA";
</script>

My aim is to read the value of variable key from this page using jsoup.
Is it possible with jsoup? If yes then how?

Solution

Since jsoup isn't a javascript library you have two ways to solve this:

A. Use a javascript library

• Pro:

  • Full Javascript support

• Con:

  • Additional libraray / dependencies

B. Use Jsoup + manual parsing

• Pro:

  • No extra libraries required
  • Enough for simple tasks

• Con:

  • Not as flexible as a javascript library

Here's an example how to get the key with jsoupand some "manual" code:

Document doc = ...
Element script = doc.select("script").first(); // Get the script part


Pattern p = Pattern.compile("(?is)key=\"(.+?)\""); // Regex for the value of the key
Matcher m = p.matcher(script.html()); // you have to use html here and NOT text! Text will drop the 'key' part


while( m.find() )
{
    System.out.println(m.group()); // the whole key ('key = value')
    System.out.println(m.group(1)); // value only
}

Output (using your html part):

key="pqRjnA"
pqRjnA

Comments

[Anil Kumar Pandey]

Hey, Jsoup + manual parsing is very good solution for this, but breaking while I am using the js variable as array. eg: keyArray = [1, 2, 3] can you please give me solution for this.

[ollo]

You can use this regex instead: (?s)(keyArray)\\s??=\\s??\\[(.*?)\\]. If defined two groups: Group 1 = variable name, group 2 = value (those within [ ]).

[user79307]

And What if I have something like abc.xyz.init({requiredJsonObjectAsAnArgument}); inside script tags and I want to parse requiredJsonObjectAsAnArgument only. Can you suggest me the applicable regex for this case?

[ollo]

Please try (?s)\\.init\\(\\{(.+?)\\}\\); - group #1 contains the requiredJsonObjectAsAnArgument.