Access website without Domain (Plesk Panel)

most hosting provider set temporary url based on the server ip address and customized domain name

https://www.motherhost.com/help/temporary-url-for-the-domain-in-plesk-control-panel/

Any domain or server name followed by /~cpanelusername/ can be used to see that user’s site. This will cause any domain on the server to show the site for the username. That’s how cPanel setup works; so we can’t prevent this method from showing someone else’s site on your domain.
Hosting with Plesk 11
http://domainname.com.ipaddress.windowshostingdns.com/

(Be sure to replace all of the above with the actual values and to have the dashes between the IP octets instead of dots.)

The IP address can be either the IP for the A record or the control panel, based on which one is actively pointing to the site as A records can direct a domain name to point to a different server.

The best way to find the temporary URL from your Plesk control panel is to do the following:

Click on the Web Sites and Domains tab.
Click on the Domain Name for the hosting settings.
In the hosting settings, look for the preview link. This will provide the proper temporary URL.

Hosting with Plesk 10

(Be sure to replace "serverIP", "cpanelusername" and "path_aka_document_root" with the actual values.)
Hosting with Plesk 11

(Be sure to replace all of the above with the actual values and to have the dashes between the IP octets instead of dots.)
Hosting with Plesk 10

(Be sure to replace "serverIP" and "otherdomain.com" with the actual values.)
Hosting with Plesk 8 and 9

(Replace "ipaddress" with your server’s IP address.)