It seems there is just only way to create a ticket form and implement from Frontend via Javascript is:
Get token access, on document: https://developer.zendesk.com/documentation/ticketing/using-the-zendesk-api/making-cross-origin-browser-side-api-requests/

in function:

function init() {

// reset page

document.getElementById('error-msg').style.display="none";

document.getElementById('details').style.display="none";

varurl=window.location.href;

if (url.indexOf('http://localhost:8080/contact.html') !==-1) {

if (url.indexOf('access_token=') !==-1) {

varaccess_token=readUrlParam(url, 'access_token');

localStorage.setItem('zauth', access_token);

varticket_id=localStorage.getItem('ticket_id');

document.getElementById('ticket-id').value =ticket_id;

window.location.hash="";

makeRequest(access_token, ticket_id);

}

if (url.indexOf('error=') !==-1) {

varerror_desc=readUrlParam(url, 'error_description');

varmsg='Authorization error:'+error_desc;

showError(msg);

}

}

}

function startAuthFlow() {

var endpoint = 'https://***.com/oauth/authorizations/new';

var url_params = '?' +

'response_type=token' + '&' +

'redirect_uri=http://localhost:8080/contact.html' + '&' +

'client_id=dfodevtest' + '&' +

'scope=' + encodeURIComponent('read write');

window.location = endpoint + url_params;

}

After that, we have access token in localstorage, named: zauth, example define variable is: zauthValue

Then when we create a POST request, the Authorization should be: Bearer + zauthValue

But this way will redirect user to the authorizations/new... page.