Untitled

function JavaScriptCode()
{
    this['init'] = init;
    function init()
    {
        console.log('init');
    }
}

void main()
{
    JsObject jsObject = new JsObject(['JavaScriptCode']);
    jsObject.callMethod('init', []);
}

<!-- Html File -->
<!DOCTYPE html>
<html>
<body>
    <script src="main.js">
    <script src="main.dart">
</body>
</html>