Case Study PHP Web Form Builder

The examples in this article describe the PHP Web form generator. Share it with everyone for your reference, the details are as follows:

1. Example:

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2. Requirements analysis

In the actual development of the project, it is often necessary to design various forms. Although it is simple to write HTML forms directly, it is relatively troublesome to modify and maintain. Therefore, you can use PHP to implement a Web form generator, so that you can customize forms with different functions according to specific needs. The specific implementation requirements are as follows:

Use multi-dimensional arrays to save form-related information
• Supported form items include text boxes, text fields, radio boxes, check boxes and 5 types of drop-down lists
• Save the tag, prompt text, attributes, option values, default values, etc. of each form item
• Encapsulate the function into a function and generate the specified form based on the passed parameters

The storage form of data determines the way the program is implemented. Therefore, according to the above development requirements, each form item can be used as an array element, and each element is described by an associative array, which are: tag, prompt text, attribute array attr, option array option and default value. default.

3. Case implementation

1. Prepare the form

The main function of the form: on the web page The area used to input information collects the information entered by the user and submits it to the back-end server for processing to realize the interaction between the user and the server. For example: shopping settlement, information search, etc. are all implemented through forms.

2. Prepare the form - create the form

A complete form is composed of form fields and form controls. Among them, the form field is defined by the form tag and is used to collect and transfer user information.

<form action="form.php" method="post" enctype="multipart/form-data">
  <!-- 各种表单控件 -->
</form>

"

The value of the action attribute can be an absolute path or a relative path. If this attribute is omitted, it means that it is submitted to the current file for processing.
• The form passed by GET method is visible in the URL address bar.
  Compared with the GET method, the data submitted by the POST method is invisible and relatively safe during interaction. Therefore, POST is usually used to submit form data.
  
The default value of the enctype attribute is application/x-www-form-urlencoded, which means that all characters are encoded before sending the form data. In addition, it can also be set to multipart/form-data (POST mode) to indicate no character encoding, especially forms containing file uploads must use this value; set to text/plain (POST mode) to transmit ordinary text.

3. Prepare the form—form control

//input控件
<input type="text" name="user" value="test">	<!-- 文本框 -->
<input type="password" name="pwd" value="">		<!-- 密码框 -->
<input type="file" name="upload">     		<!-- 文件上传域 -->
<input type="hidden" name="id" value="2"> 		<!-- 隐藏域 -->
<input type="reset" value="重置">     		<!-- 重置按钮 -->
<input type="submit" value="提交">    		<!-- 提交按钮 -->

Set different values ​​for the type attribute to get different form controls
name attribute is used Specify the name of the control to distinguish multiple identical controls in the form
The value property is used to set the default value of the form control

//input控件
<!-- 单选框 -->
<input type="radio" name="gender" value="m" checked> 男
<input type="radio" name="gender" value="w"> 女
<!-- 复选框 -->
<input type="checkbox" name="hobby[]" value="swimming"> 游泳
<input type="checkbox" name="hobby[]" value="reading"> 读书
<input type="checkbox" name="hobby[]" value="running"> 跑步

The checked property is used to set the default Selected items

//textarea控件
<textarea name="introduce" cols="5" rows="10">
<!-- 文本内容 -->
</textarea>

The textarea control is suitable for self-evaluation, comments and other functions that may require input of a large amount of information
The attributes cols and rows are used to define the height and width of the text area

//select控件
<select name="area">
  <option selected>--请选择--</option>
  <option value="Beijing">北京</option>
  <option value="Shenzhen">深圳</option>
  <option value="Shanghai">上海</option>
</select>

select is the tag that defines the drop-down list
option is the tag that defines the specific options in the drop-down list
The selected attribute is used to set the default selected item

4. Prepare the form—label mark

When writing form controls, in order to provide a better user experience, the input control is often used in conjunction with the label mark. Expand the selection of controls. For example, when selecting gender, click the prompt text "Male" or "Female", or select the corresponding radio button.

Use label tags to wrap radio buttons and prompt text, so that when you click the content in the label tag, the corresponding form control will be selected.

<label><input type="radio" name="gender" value="m">男</label>
<label><input type="radio" name="gender" value="w">女</label>

5. Multi-dimensional array

According to the demand analysis of the case, the relevant data of the form items are uniformly saved in a multi-dimensional array. Among them, numeric key names are used to distinguish different form items, and each form item is a two-dimensional associative array.

// 利用多维数组保存表单元素
[
  0 => [],	// 表单项---单选按钮
  1 => [],	// 表单项
  2 => [],	// 表单项---文本框
  3 => [],	// 表单项
  ……
];

// 每个表单项的数组结构
0 => [
  'tag' => '', 	// 标记----input、textarea、select
  'text' => '', 	// 提示文本----label标签内显示的内容
  'attr' => [],	// 属性数组----表单元素的属性，如type
  'option' => [], 	// 选项数组----单选框或复选框中的每个选项
  'default' => ''	// 默认值----默认值
],

//准备表单数组
// $elements数组保存整个表单
$elements = [
  0 => [],		// 第1个表单项数组
  1 => [],		// 第2个表单项数组
];

//文本框
0 => [
  'tag' => 'input',
  'text' => '姓　　名：',
  'attr' => ['type' => 'text', 'name' => 'user']
],

//单选框
3 => [
  'tag' => 'input',
  'text' => '性　　别：',
  'attr' => ['type' => 'radio', 'name' => 'gender'],
  'option' => ['m' => '男', 'w' => '女'],
  'default' => 'm'
 ],

option uses an associative array to save specific radio options. The key names m and w are the value attributes of the radio button, and the corresponding values ​​​​"male" and "female" are the single options. Option prompt informationThe value of default is a key name in the option associative array, indicating which item is selected by default

//复选框
4 => [
  'tag' => 'input',
  'text' => '爱　　好：',
  'attr' => ['type' => 'checkbox', 'name' => 'hobby[]'],
  'option' => ['swimming' => '游泳', 'reading' => '读书', 'running' => '跑步'],
  'default' => ['swimming', 'reading']
],

//下拉列表
5 => [
  'tag' => 'select',
  'text' => '住　　址：',
  'attr' => ['name' => 'area'],
  'option' => ['' => '--请选择--', 'BJ'=>'北京', 'SH'=>'上海', 'SZ'=>'深圳']
],

//文本域
6 => [
  'tag' => 'textarea',
  'text' => '自我介绍：',
  'attr' => ['name' => 'introduce', 'cols' => 50, 'rows' => 5]
],

//提交按钮
7 => [
  'tag' => 'input',
  'attr' => ['type' => 'submit', 'value' => '提交']
]

Automatic generation of the form

1. Automatic generation - reading $elements array

Implementation ideas

• In order to facilitate the processing of user-submitted data, each form item in $elements is merged with the specified array, so that each form item contains five keys: tag, text, attr, option and default. elements in the same order.
• According to the tag value, call the functions prefixed with "generate_" to splice the form items.
• Each form item occupies one line and returns the spliced ​​form

2. Automatic generation of forms - splicing attributes of form elements

Implementation ideas

• Define the function generate_attr($attr, $items = '' ) used to complete the splicing of form element attributes
• The key of the element in the $attr array is the attribute name, and the value of the element is the value of the attribute
• Completes the splicing of attributes and $items by traversing and returns , such as type="radio" name="gender"

3. Automatic generation of forms - splicing input elements

Implementation ideas

• Determine whether it is single selection or multi-selection based on whether it contains option elements
• If not, directly call the attribute function to complete the splicing of form items
• If so, traverse in sequence Complete the splicing of multiple options and return
  

4. Automatic generation of forms - splicing select elements

Implementation ideas

• Options for splicing drop-down lists
• Complete the complete splicing of select tags and return

5. Automatic generation of forms - splicing textarea elements

Implementation ideas

• Splicing attributes of textarea elements
• Completely splice textarea and return
  

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