How to automatically generate forms in PHP

<?php
//Form.php
class form {
    var $layout=true;//是否使用表格布局
    var $action;//表单要提交到的URL
    var $method;
    var $enctype="";
    var $name="";
    var $id="";
    var $class="";
    function form($action,$method="POST"){  //通过构造函数初始化成员变量
        $this->action=$action;
        $this->method=$method;
    }
    function form_start(){
        $text="<form action=\"{$this->action}\" method=\"{$this->method}\"";
        if($this->class!==""){
            $text.=" class=\"{$this->class}\"";
        }
        if ($this->enctype!=="") {
            $text.=" enctype=\"{$this->enctype}\"";
        }
        if($this->id!==""){
            $text.=" id=\"{$this->id}\"";
        }
        if($this->name!==""){
            $text.=" name=\"{$this->name}\"";
        }
        $text.=">\n";
        if($this->layout==true){
            $text.="<table>\n";
        }
        return $text;
    }
    function form_end(){
        if ($this->layout==true) {
            $text="\t</table>\n";
            $text.="</form>\n";
        }else {
            $text="</form>\n";
        }
        return $text;
    }
    //文本框函数
    function form_text($name,$id,$label_name,$label_for,$value=""){
        $text="<input type=\"text\" name=\"{$name}\" ";
        $text.="id=\"{$id}\" ";
        if(isset($value)){
            $text.="value=\"{$value}\" ";
        }
        $text.="/>\n";
        $label=$this->form_label($label_name,$label_for);
        $form_item=$this->form_item($label,$text);
        return $form_item;
    }
    //密码框函数
    function form_passwd($name,$id,$label_name,$label_for,$value=""){
        $text="<input type=\"password\" name=\"{$name}\" ";
        $text.="id=\"{$id}\" ";
        if(isset($value)){
            $text.="value=\"{$value}\" ";
        }
        $text.="/>\n";
        $label=$this->form_label($label_name,$label_for);
        $form_item=$this->form_item($label,$text);
        return $form_item;
    }
    //隐藏域函数
    function form_hidden($name,$id,$label_name,$label_for,$value=""){
        $text="<input type=\"hidden\" name=\"{$name}\" id=\"{$id}\" ";
        if(isset($value)){
            $text.="value=\"{$value}\" ";
        }
        $text.="/>\n";
        $label=$this->form_label($label_name,$label_for);
        $form_item=$this->form_item($label,$text);
        return $form_item;
    }
    //文件域函数
    function form_file($name,$id,$label_name,$label_for,$size=""){
        $text="<input type=\"file\" name=\"{$name}\" ";
        $text.="id=\"{$id}\" ";
        if(isset($size)){
            $text.="size=\"{$size}\" ";
        }
        $text.="/>\n";
        $label=$this->form_label($label_name,$label_for);
        $form_item=$this->form_item($label,$text);
        return $form_item;
    }
    //复选框函数
    function form_checkbox($name,$label=array(),$label_name,$label_for=""){
        $i=0;
        $text=array();
        foreach ($label as $id=>$value){
            $text[$i]="<input type=\"checkbox\" id=\"{$id}\" name=\"{$name}\" value=\"{$value}\" />";
            $text[$i].="<label for=\"{$id}\">{$value}</label>";
            $i++;
        }
        $label=$this->form_label($label_name,$label_for);
        $form_item=$this->form_item($label,$text);
        return $form_item;
    }
    //单选框函数
    function form_radio($name,$label=array(),$label_name,$label_for=""){
        $i=0;
        $text=array();
        foreach ($label as $id=>$value){
            $text[$i]="<input type=\"radio\" id=\"{$id}\" name=\"{$name}\" value=\"{$value}\" />";
            $text[$i].="<label for=\"{$id}\">{$value}</label>";
            $i++;
        }
        $label=$this->form_label($label_name,$label_for);
        $form_item=$this->form_item($label,$text);
        return $form_item;
    }
    //下拉菜单函数
    function form_select($id,$name,$options=array(),$selected=false,$label_name,$label_for,$onchange=""){
        if($onchange!==""){
            $text="<select id=\"{$id}\" name=\"{$name}\" onchang=\"{$onchange}\">\n";
        }
        else{
            $text="<select id=\"{$id}\" name=\"{$name}\">\n";
        }
        foreach ($options as $value=>$key){
            if($selected==$value){
                $text.="\t<option valute=\"{$value}\" selected=\"selected\">{$key}</option>\n";
            }elseif ($selected===false) {            
                $text.="\t<option value=\"{$value}\">{$key}</option>\n";
            }
        }
        $text.="</select>";
        $label=$this->form_label($label_name,$label_for);
        $form_item=$this->form_item($label,$text);
        return $form_item;
    }
    //多选列表函数
    function form_selectmul($id,$name,$size,$options=array(),$label_name,$label_for){
        $text="<select id=\"{$id}\" name=\"{$name}\" size=\"{$size}\" multiple=\"multiple\">\n";
        foreach ($options as $value=>$key){
            $text.="\t<option value=\"{$value}\">{$key}</option>\n";
        }
        $text.="</select>\n";
        $label=$this->form_label($label_name,$label_for);
        $form_item=$this->form_item($label,$text);
        return $form_item;
    }
    //按钮函数
    function form_button($id,$name,$type,$value,$onclick=""){
        $text="<button id=\"{$id}\" name=\"{$name}\" type=\"{$type}\"";
        if($onclick!==""){
            $text.=" onclick=&#39;{$onclick}&#39;";
        }
        $text.=">".$value;
        $text.="</button>\n";
        if($this->layout==true){
            $form_item="<tr>\n\t<th> </th><td>{$text}</td>\n</tr>\n";
        }else {
            $form_item=$text;
        }
        return $form_item;
    }
    //文本域函数
    function form_textarea($id,$name,$cols,$rows,$label_name,$label_for,$value=""){
        $text="<textarea id=\"{$id}\" name=\"{$name}\" cols=\"{$cols}\" rows=\"{$rows}\">{$value}</textarea>\n";
        $label=$this->form_label($label_name,$label_for);
        $form_item=$this->form_item($label,$text);
        return $form_item;
    }
    //文字标签函数
    function form_label($text,$for){
        if($for!==""){
            $label="<label for=\"{$for}\">{$text}：</label>";
        }else {
            $label=$text."：";
        }
        return $label;
    }
    function form_item($form_label,$form_text){
        switch ($this->layout){
            case true:
                $text="<tr>\n";
                $text.="\t<th class=\"label\">";
                $text.=$form_label;
                $text.="</th>\n";
                $text.="\t<td>";
                $text.=$form_text;
                $text.="</td>\n";
                $text.="</tr>\n";
                break;
            case false:
                $text=$form_label;
                $text.=$form_text;
                break;
        }
        return $text;
    }
    function CreateForm($form_item=array()){
        echo $this->form_start();
        foreach ($form_item as $item){
            echo $item;
        }
        echo $this->form_end();
    }
}
?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="zh" lang="zh">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
    <link rel="stylesheet" type="text/css" href="css/styles.css" />
    <title>用户登录</title>
</head>
<body>
<?php
require_once("form.php");
$form=new form($_SERVER[&#39;PHP_SELF&#39;]);   //提交到本页
$form->layout=false;                   //不使用表格布局，大家可以把这句注释掉看结果有何不同
$name=$form->form_text("userid","userid","用户名","userid");
$passwd=$form->form_passwd("passwd","passwd","密码","passwd");
$submit=$form->form_button("","submit","submit","登录");
$form_item=array($name,$passwd,$submit);
$form->CreateForm($form_item);
?>
</body>
</html>