The isPlainhost name()() function detects whether the host name in the requested URL is a plain host name or a fully qualified domain name. This function is useful if you want the browser to connect directly to local servers, as illustrated in Example 1: Proxy All Servers Except Local Hosts and Example 2: Proxy Local Servers Outside the Firewall.
host is the host name from the URL, excluding the port number only if the host name has no domain name (no dotted segments).
true if host is local; false if host is remote
isPlainhost name("host")
If host is a string like www, then the function returns true. If host is a string like www.example.com, the function returns false.