Connect qwebkit and javascript problem

atena_2019

hi to all
i am using qwebkit
i have a cpp object and export it to javascript but it does not connect to it , because it does not work
here is my code :
my cpp code :
@#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QWebFrame>
#include <QMessageBox>

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
this->setObjectName("MyWin");
connectCPPObjectToJS(this->objectName() , this);
loadUrl(QCoreApplication::applicationDirPath() + "/sura.htm");

}

void MainWindow::test()
{
QMessageBox::information(this , "a" , "hello");
}

void MainWindow::loadUrl(const QString & localpath)
{
ui->webView->load(QUrl::fromLocalFile(localpath));
}

void MainWindow::on_comboBox_currentIndexChanged(int index)
{
QString s ;
QMessageBox::information(this , "index change" , s.setNum(index));
emit sendChangedIndexToJS(index);

}

void MainWindow::connectCPPObjectToJS(const QString objectname , QObject* objecttype)
{
ui->webView->page()->mainFrame()->addToJavaScriptWindowObject( objectName() , objecttype);

}

void MainWindow::on_comboBox_textChanged(QString a)
{
QMessageBox::information(this , "text change" , a);

}

@

and here is my html code :
@
<html>

<head>
<meta http-equiv="Content-Language" content="en-us">
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
<title>مثال چهار قل</title>
[removed]
function updatesura(value){
alert("the value was changed to " + value);
}
MyWin.test();
MyWin.sendChangedIndexToJS.connect(updatesura());

[removed]

</head>

</html>
@

what is wrong ?
thanks a lot

atena_2019

i put the statement javascript "MyWin.test();" in a try catch and the error is that :
ReferenceError : can't find variable MyWin

so now i am sure that the connection is wrong . but i do not know why:(

dangelog

Quoting the docs:

bq. If you want to ensure that your QObjects remain accessible after loading a new URL, you should add them in a slot connected to the javaScriptWindowObjectCleared() signal.

atena_2019

thanks a lot . you are right

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Connect qwebkit and javascript problem