"whatYouTyped.parentNode;" can someone break this down to explain exactly what its doing thanks ?

```
function checkphone(whatYouTyped) {
var fieldset = whatYouTyped.parentNode;
var txt = whatYouTyped.value;
 if ( /^((\+\d{1,3}(-| )?\(?\d\)?(-| )?\d{1,5})|(\(?\d{2,6}\)?))(-| )?(\d{3,4})(-| )?(\d{4})(( x| ext)\d{1,5}){0,1}$/.test(txt)) {
    fieldset.className = "welldone";
    compphone=true;
} else {
    fieldset.className = "";
    compphone=false;
}

```

}