continue is used within looping structures to skip the rest of the current loop iteration and continue execution at the condition evaluation and then the beginning of the next iteration.

$i = 0;
while ($i++ < 5) {
    echo "Outer<br />\n";
    while (1) {
        echo "&nbsp;Middle<br />\n";
        while (1) {
            echo "&nbsp;&nbsp;Inner<br />\n";
            continue 3;
        }
        echo "This never gets output.<br />\n";
    }
    echo "Neither does this.<br />\n";
}