Website http post to Zebra printer

Hello,

I am trying to write a simple web page with a button to send some ZPL code to a barcode printer.
The button is on my page but nothing happens.
I i put the html code on a single file on my laptop and opening it, this works
Here is my code:

export default {
async fetch(request) {
const html = `

Print Badge
`;

},
};

export default {
async fetch(request) {
const html = `

Print Badge
`;

},
};