A single-file WebAssembly html demo

Where can I find a simplest one-file demo showing usage of WebAssembly in html?

JavaScript example is easy:

<script>
function hw() { console.log("Hello, world."); }
</script>
<button onclick="hw()">HW</button>

Is there a WebAssembly analogue?

I expect it to have something like a hard-coded byte buffer with a wasm binary, which is loaded and some trivial function of it is executed. Here is outline of what I expect:

<script>
function hw() { 
    var wasm_code = [255, 0, 128, ..., whatever, ...];
    var magic = give_me_wasm(wasm_code);
    var x = magic.my_add(2,2);
    console.log("2 + 2 = ", x); 
}
</script>
<button onclick="hw()">HW</button>

Can such demo be done, it a simple form that can be pasted in Developer Console and tried without setting up any frameworks and tools?

Done myself:

<script>
var wasm_base64;
var wasm_buffer;
var wasm;
var wasm_instance;
function hw() {
    wasm_base64 = "AGFzbQEAAAABBwFgAnx8AXwDAgEABwoBBm15X2FkZAAACgkBBwAgACABoAs=";
    wasm_buffer = Uint8Array.from(atob(wasm_base64), c => c.charCodeAt(0)).buffer;
    WebAssembly.compile(wasm_buffer).then(x => {
        wasm = x;
        wasm_instance = new WebAssembly.Instance(wasm);
        var x = wasm_instance.exports.my_add(2,2);
        console.log("2+2 = ",x);
    });
}
</script>
<button onclick="hw()">HW</button>

Here is embedded WebAssembly text form (q.wat):

(module
  (type (;0;) (func (param f64 f64) (result f64)))
  (func $myadd (type 0) (param f64 f64) (result f64)
    get_local 0
    get_local 1
    f64.add)
  (export "my_add" (func $myadd))
)

Here are command lines to generate that base64 buffer:

$ wat2wasm q.wat -o w.wasm
$ base64 -w0 w.wasm ;echo
AGFzbQEAAAABBwFgAnx8AXwDAgEABwoBBm15X2FkZAAACgkBBwAgACABoAs=

wasm and wasm_instance objects can be explored using Developer Console.

Checked in Firefox 63.0b9.