<?php
//Format a string fo ruse with a HTML class or id attribute
function str_class_id( $string, $strtolower = TRUE ){
    $string = preg_replace( '/^([^a-z])/i', 'a$1', $string );
    $string = preg_replace( '/[^a-z0-9-]/i', '-', $string );
    $string = preg_replace( '/[-]+/', '-', $string );
    $string = trim( $string, '-' );

    if( $strtolower ){ //Optionally lowercase the string
        $string = strtolower( $string );
    }

    return( $string );
}