Phantomjs disable javascript in page but enable included javascript

Question

I am using phantomjs to retrieve CSS information from a page without execute its javascript. For example here is the code snippet.

page.settings.javascriptEnabled = false;
page.open('file:///home/sample.html', function(status) {
    if (status !== 'success') {
        console.log('Unable to access network');
    } else {
        page.includeJs("file:///home/sample.js", function() {
            var class = page.evaluate(function() {
                return document.querySelector('body').className;
            });
            console.log(class);
        });
    }
}

If I disabled the javascript, the evaluate function always return null. But when I tried to enable the javascript, the evaluate function will return some value. Is there any idea to disable the javascript in the page, but my included javascript have to work ?

What do you mean by your last sentence? You want to run some javascript but not all? — WhatisSober
– WhatisSober, Commented Jun 7, 2015 at 11:20
@WhatisSober the page I opened contains javascript code. I don't want that code to be executed. But then I include some script to help me to retrieve the information I want. So i need my included javascript from phantomjs to work. — Hendra Huang
– Hendra Huang, Commented Jun 7, 2015 at 12:00

Artjom B. · Accepted Answer · 2015-06-07 12:52:34Z

4

No

page.evaluate() executes JavaScript on the page. If you disable JavaScript in PhantomJS, then you effectively can't use page.evaluate() anymore. And with it goes every way of accessing DOM elements. page.includeJs() will also not work, because it the script cannot be executed on the page.

You can still access page.content which provides access to the current page source (computed source). You may try to use some DOM library to parse the source into a DOM object¹ or if the task is simple, you may try to use Regular Expressions.

¹ Note that PhantomJS and node.js have different execution environments, so most node.js modules that deal with the DOM won't work

answered Jun 7, 2015 at 12:52

Artjom B.

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3 Comments

Gajus Over a year ago

What about removing all <script> tags from the document before either has been loaded. Is that possible? That would effectively disable JavaScript.

Artjom B. Over a year ago

@Gajus If a script tag is in the DOM then it is most likely already executed. There is a very short window where the initial <script> is delivered to the browser and the remaining content of the script is still in transit. This is true for script elements directly contain JavaScript. If a script element has a src attribute, then an additional JavaScript file will be downloaded, which you can abort(), but it will be tricky. I wouldn't say that it disables JavaScript. It's just preventing it to be executed.

Gajus Over a year ago

Thank you for the suggestion. I have added an answer suggesting to use HTTP proxy to achieve the above. stackoverflow.com/a/41893648/368691

Community · Accepted Answer · 2017-05-23 10:29:37Z

1

As suggested by Artjom, there is no way to disable execution of the target website JavaScript without disabling PhantomJS ability to execute JavaScript on the page. However, there is a simple way to ensure that no scripts are executed by the target website (which achieves the same result, at the end).

Create a HTTP proxy that intercepts all requests.
Detect responses with Content-Type: text/html.
Remove all <script> tags from the document.

You can configure phantomjs to use proxy using --proxy configuration.

Use http-proxy to create a proxy server.

Use cheerio to remove, comment out, or otherwise invalidate the <script> tags.

edited May 23, 2017 at 10:29

CommunityBot

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answered Jan 27, 2017 at 12:07

Gajus

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