This is just a simple PHP function that verify a input string to see if it’s a valid URL with right format or not. It uses regex expression to match.
This function works for almost cases (website url) but it’s not exhaustive, I’m sure 
PHP Validate URL function
<?php
function validate_url($url)
{
if (!preg_match("#^http(s)?://[a-z0-9-_.]+\.[a-z]{2,4}#i",$url))
return "0";
return "1";
}
?> |
Usage
<?php
$url = "http://4rapiddev.com";
if(validate_url($url) == "1")
echo "It's a valid URL";
else
echo "It is NOT a valid URL";
?> |
Output
