HTML5 canvas score counter

Good evening again! In the current project I am working I need a simple score counter. 

I have created a simple asc3 score couter with the following code:

stop();

var total:int=0;
scoreText.text = total.toString();

upbutton.addEventListener(MouseEvent.CLICK, fl_MouseClickHandler);

function fl_MouseClickHandler(event:MouseEvent):void
{
total = total+1;
scoreText.text = total.toString();
}

downbutton.addEventListener(MouseEvent.CLICK, fl_MouseClickHandler_2);

function fl_MouseClickHandler_2(event:MouseEvent):void
{
total = total-1;
scoreText.text = total.toString();
}

And I try to remake it in html5 canvas. I did the following code:

this.stop();

var total int=0;
this.scoreText.text = total.toString();

/* Mouse Click Event

this.upbutton_button.addEventListener("click", fl_MouseClickHandler.bind(this));

function fl_MouseClickHandler()
{
this.total = total+1;
this.scoreText.text = total.toString();
}

this.downbutton_button.addEventListener("click", fl_MouseClickHandler_2.bind(this));

function fl_MouseClickHandler_2()
{
this.total = total-1;
this.scoreText.text = total.toString();
}

And of course it does not work! Can you please help to understand where are the mistakes? The console of chrome gives the following:

Please help if you know how to proceed.