RequestInterceptor not working properly

// request.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QWebEngineUrlRequestInterceptor>

class WebUrlRequestInterceptor : public QWebEngineUrlRequestInterceptor
{
    Q_OBJECT

public:
    WebUrlRequestInterceptor(QObject *p = Q_NULLPTR);
    void interceptRequest(QWebEngineUrlRequestInfo &info);
};

#endif // MAINWINDOW_H


// request.cpp
#include "request.h"

WebUrlRequestInterceptor::WebUrlRequestInterceptor(QObject *p)
  :QWebEngineUrlRequestInterceptor(p)
{
}

void WebUrlRequestInterceptor::interceptRequest(QWebEngineUrlRequestInfo &info) {
   const QString scheme = info.requestUrl().scheme();
   if(scheme != "http" && scheme != "https") info.block(true);
}



// main.cpp
#include <QApplication>
#include <QWebEngineProfile>
#include <QWebEngineView>
#include "request.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    WebUrlRequestInterceptor *wuri = new WebUrlRequestInterceptor;
    QWebEngineProfile::defaultProfile()->setRequestInterceptor(wuri);

    QWebEngineView w;
    w.setUrl(QUrl("javascript:alert('test')"));
    w.show();
    return a.exec();
}