11.18. HTML forms and input

发布时间 ： 2025-10-25 13:33:16 UTC      

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HTML forms are used to collect different types of user input.

The HTML form represents an area in the document that contains interactive controls that send the information collected by the user to the Web server.

11.18.1. HTML form

A form is an area that contains form elements.

Form elements allow users to enter content in the form, such as text fields (textarea), drop-down lists, radio-buttons boxes, checkboxes, and so on.

Forms use form tags

to set up:

Example 

<form> . *input element* . form>      
 
  11.18.2.  HTML form-input element  
 
 In most cases, the form tag used is the input tag (< input >). 
 
 The input type is defined by the type type. Most of the frequently used input types are as follows: 
 
 
 
  11.18.3.  Text field  
 
 The text field is set by the < input type= “text” > tag, which is used when users type letters, numbers, and so on into the form. 
 
 
 
<form> First name: <input type="text" name="firstname"><br> Last name: <input type="text" name="lastname"> form>    
 The browser displays as follows: 
 
 First name: Last name: 
 
 Note: the form itself is not visible. Also, in most browsers, the default width of the text field is 20 characters. 
  
 
  11.18.4.  Password field  
 
 The password field is defined by the label < input type= “password” >: 
 
 
 
<form> Password: <input type="password" name="pwd"> form>    
 The browser displays as follows: 
 
 Password: 
 
 Note: password field characters are not displayed in clear text, but are replaced by asterisks or dots. 
  
 
  11.18.5.  Radio button  
 
 The < input type= “radio” > tag defines the form radio check box option 
 
 
 
<form> <input type="radio" name="sex" value="male">Male<br> <input type="radio" name="sex" value="female">Female form>    
 The browser displays as follows: 
 
 Male 
 
 Female 
  
 
  11.18.6.  Check box  
 
 < input type= “checkbox” > defines a check box. The user needs to select one or more options from several given selections. 
 
 
 
<form> <input type="checkbox" name="vehicle" value="Bike">I have a bike<br> <input type="checkbox" name="vehicle" value="Car">I have a car form>    
 The browser displays as follows: 
 
 I have a bike 
 
 I have a car 
  
 
  11.18.7.  Submit button  
 
 < input type= “submit” > defines the submit button. 
 
 When the user clicks the confirm button, the contents of the form are transferred to another file. The action attribute of the form defines the file name of the destination file. This file, defined by the action attribute, usually processes the input data received. : 
 
 
 
<form name="input" action="html_form_action.php" method="get"> Username: <input type="text" name="user"> <input type="submit" value="Submit"> form>    
 The browser displays as follows: 
 
 Username: if you type a few letters in the text box above, and then click the confirm button, the input data will be transferred to the “html_form_action.php” page. The page displays the results of the input. 
  
 
  11.18.8.  HTML form label  
 
 New: new HTML5 tag 
 
      
  
 Label 
 		  
 Description 
 		 
   
  
 < form > 
 		  
 Define a form for user input 
 		 
 
  
 < input > 
 		  
 Define input field 
 		 
 
  
 < textarea > 
 		  
 Define a text field (a multiline input control) 
 		 
 
  
 < label > 
 		  
 Defines the tag of the < input > element, which is usually the input title 
 		 
 
  
 < fieldset > 
 		  
 Defines a set of related form elements and contains them using a bounding box 
 		 
 
  
 < legend > 
 		  
 Defines the title of the < fieldset > element 
 		 
 
  
 < select > 
 		  
 Defines a list of drop-down options 
 		 
 
  
 < optgroup > 
 		  
 Define option groups 
 		 
 
  
 < option > 
 		  
 Define options in the drop-down list 
 		 
 
  
 < button > 
 		  
 Define a click button 
 		 
 
  
 < datalist > New 
 		  
 Specify a predefined list of input control options 
 		 
 
  
 < keygen > New 
 		  
 Defines the key pair generator field for the form 
 		 
 
  
 < output > New 
 		  
 Define a calculation result 
 		 
  
 
  
                
                

                    

                        

                            
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                            11.18. HTML forms and input 
                        

                    

                

            
        
        

            

    
        
        

            

                

                    
                        
                            
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