Before working with the Singleton model of the form element factory, it’s best to define all of the form element classes, suitable for use in PHP4. Since they’re closely similar to their counterparts in PHP5, this shouldn’t present any difficulties. Here they are:

// class textinput
class textinput{
    var $html;
    function textinput($attributes=array()){
        if(count($attributes)<1){
            trigger_error('Invalid number of
attributes');
exit();
        }
        $this->html='<input type="text" ';
        foreach($attributes as $attribute=>$value){
            $this->html.=$attribute.'="'.$value.'" ';
        }
        $this->html.='/>';
    }
    function getHTML(){
        return $this->html;
    }
}
// class password input
class passwordinput{
    var $html;
    function passwordinput($attributes=array()){
        if(count($attributes)<1){
            trigger_error('Invalid number of
attributes');
exit();
        }
        $this->html='<input type="text" ';
        foreach($attributes as
$attribute=>$value){
            $this->html.=$attribute.'="'.$value.'" ';
        }
        $this->html.='/>';
    }
    function getHTML(){
        return $this->html;
    }
}
// class hidden input
class hiddeninput{
    var $html;
    function textinput($attributes=array()){
        if(count($attributes)<1){
            trigger_error('Invalid number of
attributes');
exit();
        }
        $this->html='<input type="hidden" ';
        foreach($attributes as $attribute=>$value){
            $this->html.=$attribute.'="'.$value.'" ';
        }
        $this->html.='/>';
    }
    function getHTML(){
        return $this->html;
    }
}
// class file input
class fileinput{
    var $html;
    function fileinput($attributes=array()){
        if(count($attributes)<1){
            trigger_error('Invalid number of
attributes');
exit();
        }
        $this->html='<input type="file" ';
        foreach($attributes as
$attribute=>$value){
            $this->html.=$attribute.'="'.$value.'" ';
        }
        $this->html.='/>';
    }
    function getHTML(){
        return $this->html;
    }
}
// class image input
class imageinput{
    var $html;
    function imageinput($attributes=array()){
        if(count($attributes)<1){
            trigger_error('Invalid number of
attributes');
exit();
        }
        $this->html='<input type="image" ';
        foreach($attributes as
$attribute=>$value){
            $this->html.=$attribute.'="'.$value.'" ';
        }
        $this->html.='/>';
    }
    function getHTML(){
        return $this->html;
    }
}
// class radio button
class radiobutton{
    var $html;
    function radiobutton($attributes=array()){
        if(count($attributes)<1){
            trigger_error('Invalid number of
attributes');
            exit();
        }
        $this->html='<input type="radio" ';
        foreach($attributes as $attribute=>$value){
            $this->html.=$attribute.'="'.$value.'" ';
        }
        $this->html.='/>';
    }
    function getHTML(){
        return $this->html;
    }
}
// class check box
class checkbox{
    var $html;
    function checkbox($attributes=array()){
        if(count($attributes)<1){
            trigger_error('Invalid number of
attributes');
exit();
        }
        $this->html='<input type="checkbox" ';
        foreach($attributes as
$attribute=>$value){
            $this->html.=$attribute.'="'.$value.'" ';
        }
        $this->html.='/>';
    }
    function getHTML(){
        return $this->html;
    }
}

All right, let’s pause for a moment and relax. At this point, most of the form element classes has been listed, so the walk through the source code is almost finished. There are a few more classes to be defined yet, so keep reading.