Bug 39717 – very slow QVariant QWebFrame::evaluateJavaScript(const QString& scriptSource) method.

• Status: RESOLVED
• Resolution: INVALID
• Component: WebKit Qt

Hi all,

I noticed that the QWebFrame method evaluateJavaScript(const QString& scriptSource) is very slow.

consider this code:

class MyClass : public QWebFrame {

    void do() {
            QString script = QString(" \
                      var main = document.getElementById('main'); \
                      var newDivElement = document.createElement('div'); \
                      main.appendChild(newDivElement); ");

            //first loop execution time > 5 minutes  !!!!!
            for(int i=0;i<500;i++) 
                 evaluateJavaScript(script);

            //second loop execution time < 0.1 sec
            for(int i=0;i<500;i++) 
                 evaluateJavaScript(script + "false;");
    }
}

it looks like that the calculation of the result (JSC::Bindings::convertValueToQVariant)
is very slow.
maybe a lazy calculation would be better.

Best Regards

[Sriram]

Seems to be a performance issue.  Should be picked up.

[vincent]

as I see, the worst place of performance is tampering the html. eg.(JQUERY)
    $("<a class='savetolocal'>SAVE</a>").insertAfter(current);

i hope the qwebkit can offer some interface to extend the brower. like firefox's extension. user can excute extra script after loading page.

[Jocelyn Turcotte]

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