This is one of those nifty little functions that you never seem to remember off the top of your head. Basically it is shorthand for when you want to print a variable if it is set or exists. Instead of doing a bunch of is/or checks on your variable, try this instead:

function issetor(&$var, $default = false) {
    return isset($var) ? $var : $default;
}

Usage:

echo issetor($variable);

Or in a HTML-template:

<span class="name"><?=issetor($name)?></span>

Since the function takes two arguments, the variable itself and a default value, you could change the default behaviour if you want.

(Kudos to NikiC at Stackoverflow.)