function strstr (haystack, needle, bool) {
    var pos = 0;
    
    haystack += '';
    pos = haystack.indexOf( needle );
    if (pos == -1) {
        return false;
    } else{
        if (bool){
            return haystack.substr( 0, pos );
        } else{
            return haystack.slice( pos );
        }
    }
}