I've been trying to generate a PDF using the wkhtmltopdf tool (/). The page from which I want to generate a PDF using jQuery and has some initializations using a jQuery.ready() function, something like this:

jQuery(function() {
    // do something
});

However, when I try to generate a PDF from the page the script is not executed. I've tried setting a delay to wait for the JavaScript to be executed with the option:

--javascript-delay 30000

But the result is the same.

When I've enabled wkhtmltopdf's JavaScript debugging option I get a warning, which I'm not sure if it's related to the problem:

Warning: undefined:0 TypeError: 'null' is not an object

Has anyone encountered this problem? Is there some kind of workaround?

EDIT: Seems the problem is caused by the error Warning: undefined:0 TypeError: 'null' is not an object. I've managed to print the error on the PDF using:

window.onerror = function(error, url, line) {
    $('body').before('<b> Error: ' + error + '</b> <br />');
    $('body').before('<b> Url: ' + url + '</b> <br />');
    $('body').before('<b> Line: ' + line + '</b> <br />');
    console.log(error, ' ', url, ' ', line);
};

But the information is very limited and I have no idea what might cause it:

Error: TypeError: 'null' is not an object
Url: undefined
Line: 0 

I've been trying to generate a PDF using the wkhtmltopdf tool (http://wkhtmltopdf/). The page from which I want to generate a PDF using jQuery and has some initializations using a jQuery.ready() function, something like this:

jQuery(function() {
    // do something
});

However, when I try to generate a PDF from the page the script is not executed. I've tried setting a delay to wait for the JavaScript to be executed with the option:

--javascript-delay 30000

But the result is the same.

When I've enabled wkhtmltopdf's JavaScript debugging option I get a warning, which I'm not sure if it's related to the problem:

Warning: undefined:0 TypeError: 'null' is not an object

Has anyone encountered this problem? Is there some kind of workaround?

EDIT: Seems the problem is caused by the error Warning: undefined:0 TypeError: 'null' is not an object. I've managed to print the error on the PDF using:

window.onerror = function(error, url, line) {
    $('body').before('<b> Error: ' + error + '</b> <br />');
    $('body').before('<b> Url: ' + url + '</b> <br />');
    $('body').before('<b> Line: ' + line + '</b> <br />');
    console.log(error, ' ', url, ' ', line);
};

But the information is very limited and I have no idea what might cause it:

Error: TypeError: 'null' is not an object
Url: undefined
Line: 0 

• javascript
• jquery
• wkhtmltopdf

• 1 Sounds like the JavaScript in the page does not work with Qt's somewhat old webkit. Can you add the code or a link to the page? – jgillich Commented May 21, 2014 at 8:30
• Sadly, I can't provide the code of the web page. Is there a way to see a meaningful stack trace? Because this error is pletely useless. – Ivo Commented May 21, 2014 at 12:04
• --debug-javascript maybe? You could also try a QtWebKit-based browser like Arora (code.google./p/arora), which has WebKit's inspector. – jgillich Commented May 21, 2014 at 12:23
• Thanks, gonna try arora. As for --debug-javascript I've tried that and returns the same error as the one I posted. – Ivo Commented May 21, 2014 at 12:56

1 Answer 1

The problem turned out to be that Qt doesn't support localStorage, so one of the initialization scripts failed which cause the jQuery.ready() not being executed.

I've managed to debug it with a browser with Qt support: QtWeb. (Tried Arora as well, couldn't run it on my system).