如何确保它只是字符串中的一个http：//？

Question

How can I make sure that it is only one http:// in a string?

$url = "http://mysite.com/http://http://mysite.com/";

# set the regex for checking.
$regex = '/^\bhttp:\b\/\/.*/';

# reject the url address if it doesn't match
if (!preg_match($regex, $url)) echo 'false';

Answer 1

You can use strrpos:

if (strrpos($url, "http://") > 0) {
   // reject
 }