[DaveChild]

Originally Posted by freelancr

Validate E-Mail Address:

That email validation function was originally from my site, and is a bit out of date now (especially since the opening up of the TLD system). I rewrote the code and released it a little while ago under an open source license - see addedbytes.com/blog/email-address-validation-v2/

Here's a couple of functions I find useful. They add and remove variables from querystrings (great if you're dynamically building querystrings, especially on listing pages with listing options).

Add a Variable to a Querystring

PHP Code:

function add_querystring_var($url, $key, $value) {
    $url = preg_replace('/(.*)(\?|&)' . $key . '=[^&]+?(&)(.*)/i', '$1$2$4', $url . '&');
    $url = substr($url, 0, -1);
    if (strpos($url, '?') === false) {
        return ($url . '?' . $key . '=' . $value);
    } else {
        return ($url . '&' . $key . '=' . $value);
    }
} 


Remove a Variable from a Querystring

PHP Code:

function remove_querystring_var($url, $key) {
    $url = preg_replace('/(.*)(\?|&)' . $key . '=[^&]+?(&)(.*)/i', '$1$2$4', $url . '&');
    $url = substr($url, 0, -1);
    return ($url);
}