PHP检查域名正则表达式（无TLD部分）

Question

I am using this code to validate urls:

if(!filter_var($check_url, FILTER_VALIDATE_URL))
{ echo "URL is not valid"; }
else { echo "OK, valid"; }

Now in most case this is OK, but this will parse: http://www.--tester.com as A VALID DOMAIN ? and dashes are not allowed at the beginning !?

is there a regular expression that will check only NAME (without extension part as it will register only .com domains so that is automatically added and no need to check for it)... so only to check actual name if it is "good to go"...

I guess that input has to be checked only for letters and numbers and dashes (but only if they are NOT AT THE BEGINNING) no dots and other characters.

Answer 1

抱歉，有人需要吗？

^([a-zA-Z0-9][-a-zA-Z0-9]*[a-zA-Z0-9])$