5. Html form tag_html/css_WEB-ITnose-HTML Tutorial-php.cn

Home

Web Front-end

HTML Tutorial

5. Html form tag_html/css_WEB-ITnose

WBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWB

Jun 24, 2016 am 11:45 AM

The main function of form and form controls is to collect user experience. When the user submits the form, the content entered by the user will be submitted to the remote server as request parameters.

1, form tag

: Create a form. This element will not generate a visual interface, but other controls must be placed in this tag. Commonly used attributes:
action: This attribute is required and is used to specify the address to which the form is submitted when the confirmation button of the stand-alone form is used. It can be an absolute address or a relative address.
method: used to specify what type of request to send when submitting a form, which can be get or post. The difference between get and post is mentioned in my http blog, so I won’t go into details here.
enctype: used to specify the character set used when encoding form content. By default, form data is encoded as "application/x-www-form-urlencoded": that is, all characters are encoded before being sent to the server (spaces are converted to " " plus signs, special characters are converted to ASCII HEX values )
There are three attribute values for this attribute:
application/x-www-form-urlencoded: Encode all characters before sending (default)
multipart/form-data: Do not encode characters, use This value must be used when a form contains a file upload control.
text/plain spaces are converted to " " plus signs, but special characters are not encoded.
name: The unique name of the form, it is recommended to keep the same as the id.
Target: How to open the url, _self, _blank, _top, _parent.
Regarding this form tag, one thing that needs to be emphasized is how the form control is converted into the corresponding request parameter. The specific rules are as follows:
1. Each form control with a name attribute corresponds to a request parameter, and there is no name attribute. The form control will not generate request parameters. If multiple form controls repeat a name attribute value, then only one request parameter will be generated, but this parameter has multiple values.
2. The name attribute of the form control specifies the request parameter name, and the value specifies the request parameter value.
3. If a form control sets the disabled="disabled" attribute, this form control will no longer generate request parameters.

2, input tag

element is the most versatile among form controls. The following input elements are generated through this tag . This tag is an empty tag.
1. Single-line text box: type="text"
2. Password input box: type="password"
3. Hidden field: type="hidden"
4. Radio button: type="radio"
5. Check box: type="checkbox"
6. Image field: type="image"
7. File upload field: type="file"
8 , submit, reset, no action button: type="submit", type="reset", type="button"
The element can specify core attributes such as id, style, class, etc., and can also specify Onclick, onfocus, onblur and other event attributes are as follows:
1. checked, used to set whether single selection and multi-selection are selected
2. disabled, used to disable this element
3. maxlength, used to specify the maximum number of characters allowed to be entered in the text box
4. readonly, read-only mode, cannot be modified
5. size, specifies the width of the element
6. src, image domain display The url of the image
7. align, the alignment of the image field
The following is an html containing the above elements:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>表单相关标签</title></head><body><form action="" method="get">单行文本框：<input type="text" name="userName" id="userName" /><br />不能编辑的文本框：<input type="text" name="userName1" id="userName1" readonly="readonly" /><br />密码框：<input type="password" name="passWord" id="passWord" /><br />隐藏域：<input type="hidden" name="linkin_id" id="linkin_id" /><br />单选：<input type="radio" name="age" id="age1" value="男" />男<input type="radio" name="age" id="age2" value="女" />女<br />多选：<input type="checkbox" name="age1" id="age3" value="男" />男<input type="checkbox" name="age1" id="age4" value="女" />女<br />文件上传域：<input type="file" /><br />图像域：<input type="image" src="" /><br />4个按钮：<input type="submit" value="提交" name="button1" /><input type="submit" value="提交" name="button2" disabled="disabled" /><input type="reset" value="重置" name="button3" /><input type="button" value="无动作" name="button4" /></form></body></html>

Copy after login

3. List box and drop-down menu

generates a list box or a drop-down menu is determined by the above two elements. If size or multiple is specified, then a list box is generated, otherwise it is a drop-down menu.
: an option group. label, required, used to specify the label of this option group.
The following is an html containing the above tags:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>下拉相关标签</title></head><body>	<form action="" method="get">		下拉：		<select>			<option value="LinkinPark">林肯</option>			<option value="NightWish">夜愿</option>		</select>		列表框1：		<select multiple="multiple">			<option value="LinkinPark">林肯</option>			<option value="NightWish">夜愿</option>		</select>		列表框2：		<select multiple="multiple"size="10">			<optgroup label="名字">			<option value="LinkinPark">林肯</option>			<option value="NightWish">夜愿</option>			</optgroup>			<optgroup label="国家">			<option value="LinkinPark">美国</option>			<option value="NightWish">芬兰</option>			</optgroup>		</select>	</form></body></html>

Copy after login

4. Use textarea to define the text area

之间的内容将作为所对应的请求参数的参数值。
关于这个标签还是经常会用到的，在以前我写表单的时候，将单行的文本框拉长拉宽，但是我们在输入的时候也只能是一行，不能换行的，忽忽。
以下是包含这个标签的一份html：

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>多行文本框相关标签</title></head><body>	<form action="" method="get">		单行文本框：<input type="text" size="20" height="20" /><br />		多行文本框：<textarea rows="10" cols="20"></textarea>	</form></body></html>

Copy after login

5，使用label定义标签

用于在表单元素中定义标签，这些标签只是对其他可以生成请求参数的控件来做说明的，本身是不会产生请求参数的，所以不要为元素指定value的属性值。
从表面上看，元素只是输出普通文本，其实他最大的作用就是，当我们点击生成的文本时，他说关联的表单控件将自动获得焦点。
让标签和表单控件关联有2种方式：
1，隐式使用for属性：设置标签的for属性指向所关联表单控件的id属性值。
2，显式关联：将普通文本，表单控件丢在标签内部就可以了。关于这2种方式推荐使用第一种，也就是使用for来隐式关联，因为后面一种可能在ie下不兼容。
以下是包含上面标签的一份html：

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>label相关标签</title></head><body>	<form action="" method="get">		<label for="huhu">单行文本框：</label>		<input type="text" size="20" height="20" id="huhu" /><br />		<label>多行文本框：<textarea rows="10" cols="20"></textarea></label>	</form></body></html>

Copy after login

6，使用button定义按钮

元素用于定义一个按钮，在这个标签的内部可以包含普通的文本，文本格式化标签，图像等内容，这也就是

Statement of this Website

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress images for free

Clothoff.io

AI clothes remover

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)

2 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Repo: How To Revive Teammates

4 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Hello Kitty Island Adventure: How To Get Giant Seeds

4 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

How Long Does It Take To Beat Split Fiction?

3 weeks ago By DDD

R.E.P.O. Save File Location: Where Is It & How to Protect It?

3 weeks ago By DDD

Hot Tools

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Hot Topics

Where is the login entrance for gmail email?

7337

Java Tutorial

1627

CakePHP Tutorial

1352

Laravel Tutorial

1265

PHP Tutorial

1209

Related knowledge

Difficulty in updating caching of official account web pages: How to avoid the old cache affecting the user experience after version update? Mar 04, 2025 pm 12:32 PM

The official account web page update cache, this thing is simple and simple, and it is complicated enough to drink a pot of it. You worked hard to update the official account article, but the user still opened the old version. Who can bear the taste? In this article, let’s take a look at the twists and turns behind this and how to solve this problem gracefully. After reading it, you can easily deal with various caching problems, allowing your users to always experience the freshest content. Let’s talk about the basics first. To put it bluntly, in order to improve access speed, the browser or server stores some static resources (such as pictures, CSS, JS) or page content. Next time you access it, you can directly retrieve it from the cache without having to download it again, and it is naturally fast. But this thing is also a double-edged sword. The new version is online,

How do I use HTML5 form validation attributes to validate user input? Mar 17, 2025 pm 12:27 PM

The article discusses using HTML5 form validation attributes like required, pattern, min, max, and length limits to validate user input directly in the browser.

What are the best practices for cross-browser compatibility in HTML5? Mar 17, 2025 pm 12:20 PM

Article discusses best practices for ensuring HTML5 cross-browser compatibility, focusing on feature detection, progressive enhancement, and testing methods.

How to efficiently add stroke effects to PNG images on web pages? Mar 04, 2025 pm 02:39 PM

This article demonstrates efficient PNG border addition to webpages using CSS. It argues that CSS offers superior performance compared to JavaScript or libraries, detailing how to adjust border width, style, and color for subtle or prominent effect

What is the purpose of the <datalist> element? Mar 21, 2025 pm 12:33 PM

The article discusses the HTML <datalist> element, which enhances forms by providing autocomplete suggestions, improving user experience and reducing errors.Character count: 159

What is the purpose of the <meter> element? Mar 21, 2025 pm 12:35 PM

The article discusses the HTML <meter> element, used for displaying scalar or fractional values within a range, and its common applications in web development. It differentiates <meter> from <progress> and ex

How do I use the HTML5 <time> element to represent dates and times semantically? Mar 12, 2025 pm 04:05 PM

This article explains the HTML5 <time> element for semantic date/time representation. It emphasizes the importance of the datetime attribute for machine readability (ISO 8601 format) alongside human-readable text, boosting accessibilit

What is the purpose of the <progress> element? Mar 21, 2025 pm 12:34 PM

The article discusses the HTML <progress> element, its purpose, styling, and differences from the <meter> element. The main focus is on using <progress> for task completion and <meter> for stati

See all articles