some ts example

greeter.ts

class Greeter {
    greeting: string;
    constructor(message: string) {
        this.greeting = message;
    }
    greet() {
        return "Hello, " + this.greeting;
    }
}

let classof = (instance) => instance.constructor.name


let greeter = new Greeter("world");

let button = document.createElement('button');
let result = document.createElement('textarea');
result.rows = 30
result.cols=30
function log(fmt: string, ...args: any[]): void {
    let s = fmt+args[0]
    result.value = result.value +"\n"+ s
}

button.textContent = "RUN";
button.onclick = function() {
    console.log(greeter.greet())
    var anum: number = 3
    var astr: string = 'hello'
    log('instance class is ', classof(greeter))
    log('anum class=', classof(anum))
    log('astr=', classof(astr))
}

document.body.appendChild(button);
document.body.appendChild( result)