Backend Development
PHP Tutorial
A brief discussion on how to use PHP to access and operate DOM (1)_PHP Tutorial
A brief discussion on how to use PHP to access and operate DOM (1)_PHP Tutorial
The DOM tree defines the logical structure of documents and controls how you access and manipulate these documents. Using the DOM, developers can create XML or HTML documents, manipulate their results, and add, modify, and delete document elements and content. The DOM can be accessed from any programming language. This article uses the PHP 5 DOM extension, which is part of the PHP core, so there is no need to install other software besides PHP.
DOM tree nodes follow XML naming conventions, such as:
1. Document node--represents the DOMDocument interface
2. Element node--represents the DOMElement interface
3. Attribute node--represents the DOMAttr interface
4. Comment node--represents the DOMComment interface
5. Text node--represents the DOMText interface
Extracting elements
This section introduces how to extract elements and values from the DOM tree. This article uses Book.xml as an example to illustrate, and its content is shown in Listing 1.
List 1 Book.xml
<ol class="dp-xml"> <li class="alt"> <span><strong><font color="#006699"><span class="tag"><?</SPAN><SPAN class=tag- name>xml</SPAN></FONT></STRONG><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>version</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"1.0"</FONT></SPAN><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>encoding</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"UTF-8"</FONT></SPAN><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>standalone</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>"yes"</FONT></SPAN><SPAN> </SPAN><SPAN class=tag><STRONG><FONT color=#006699>?></span></font></strong></span><span> </span> </li> <li> <span></span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag- name>book</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li class="alt"> <span></span><span class="comments"><font color="#008200"><!--XML Processing [part I] --></font></span><span> </span> </li> <li> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag- name>name</SPAN><SPAN class=tag>></span></font></strong><span>XML Processing I</span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>name</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>author</SPAN><SPAN class=tag>></span></font></strong><span>John Smith Jr.</span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>author</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>publisher</SPAN><SPAN class=tag>></span></font></strong><span>HisOwnTM</span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag- name>publisher</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>ISBN</SPAN><SPAN class=tag>></span></font></strong><span>111-222-333-4441</span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>ISBN</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>contents</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag- name>chapter_I</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>title</SPAN><SPAN class=tag>></span></font></strong><span>What is XML about ?</span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>title</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag- name>content</SPAN><SPAN class=tag>></span></font></strong><span>XML (Extensible Markup Language) is a ...</span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>content</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li> <span> </span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>chapter_I</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag- name>chapter_II</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>title</SPAN><SPAN class=tag>></span></font></strong><span>SAX</span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag- name>title</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag- name>content</SPAN><SPAN class=tag>></span></font></strong><span>SAX is a simple API for ...</span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>content</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li> <span> </span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>chapter_II</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag- name>chapter_III</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>title</SPAN><SPAN class=tag>></span></font></strong><span>StAX</span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag- name>title</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag- name>content</SPAN><SPAN class=tag>></span></font></strong><span>Much powerful and flexible, StAX, is very...</span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>content</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li> <span> </span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>chapter_III</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag- name>chapter_IV</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>title</SPAN><SPAN class=tag>></span></font></strong><span>DOM </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>subtitle</SPAN><SPAN class=tag>></span></font></strong><span>DOM concept </span> </li> <li> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>continut</SPAN><SPAN class=tag>></span></font></strong><span>Starting to use DOM...</span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>continut</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag -name>subtitle</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>subchapter_IV_I</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>title</SPAN><SPAN class=tag>></span></font></strong><span>First DOM application...</span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>title</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li> <span> </span><st rong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>content</SPAN><SPAN class=tag>></span></font><span>Here it is your first DOM application...</span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>content</SPAN><SPAN class=tag>></span></font></strong><span> </span><li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag -name>subchapter_IV_I</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li> <span> </span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>title</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag- name>chapter_IV</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li> <span> </span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag- name>end</SPAN><SPAN class=tag>></span></font></strong><span>The end...</span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>end</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>contents</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li> <li> <span></span><span class="comments"><font color="#008200"><!-- See you in XML Processing [part II] --></font></span><span> </span> </li> <li class="alt"> <span></span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>book</SPAN><SPAN class=tag>></span></font></strong><span> </span> </li></st> </li> </ol>
First download the PHP code compression package used in this article,
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
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
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
1664
14
1423
52
1318
25
1269
29
1248
24
Explain JSON Web Tokens (JWT) and their use case in PHP APIs.
Apr 05, 2025 am 12:04 AM
JWT is an open standard based on JSON, used to securely transmit information between parties, mainly for identity authentication and information exchange. 1. JWT consists of three parts: Header, Payload and Signature. 2. The working principle of JWT includes three steps: generating JWT, verifying JWT and parsing Payload. 3. When using JWT for authentication in PHP, JWT can be generated and verified, and user role and permission information can be included in advanced usage. 4. Common errors include signature verification failure, token expiration, and payload oversized. Debugging skills include using debugging tools and logging. 5. Performance optimization and best practices include using appropriate signature algorithms, setting validity periods reasonably,
Explain late static binding in PHP (static::).
Apr 03, 2025 am 12:04 AM
Static binding (static::) implements late static binding (LSB) in PHP, allowing calling classes to be referenced in static contexts rather than defining classes. 1) The parsing process is performed at runtime, 2) Look up the call class in the inheritance relationship, 3) It may bring performance overhead.
What are PHP magic methods (__construct, __destruct, __call, __get, __set, etc.) and provide use cases?
Apr 03, 2025 am 12:03 AM
What are the magic methods of PHP? PHP's magic methods include: 1.\_\_construct, used to initialize objects; 2.\_\_destruct, used to clean up resources; 3.\_\_call, handle non-existent method calls; 4.\_\_get, implement dynamic attribute access; 5.\_\_set, implement dynamic attribute settings. These methods are automatically called in certain situations, improving code flexibility and efficiency.
PHP and Python: Comparing Two Popular Programming Languages
Apr 14, 2025 am 12:13 AM
PHP and Python each have their own advantages, and choose according to project requirements. 1.PHP is suitable for web development, especially for rapid development and maintenance of websites. 2. Python is suitable for data science, machine learning and artificial intelligence, with concise syntax and suitable for beginners.
PHP in Action: Real-World Examples and Applications
Apr 14, 2025 am 12:19 AM
PHP is widely used in e-commerce, content management systems and API development. 1) E-commerce: used for shopping cart function and payment processing. 2) Content management system: used for dynamic content generation and user management. 3) API development: used for RESTful API development and API security. Through performance optimization and best practices, the efficiency and maintainability of PHP applications are improved.
PHP: A Key Language for Web Development
Apr 13, 2025 am 12:08 AM
PHP is a scripting language widely used on the server side, especially suitable for web development. 1.PHP can embed HTML, process HTTP requests and responses, and supports a variety of databases. 2.PHP is used to generate dynamic web content, process form data, access databases, etc., with strong community support and open source resources. 3. PHP is an interpreted language, and the execution process includes lexical analysis, grammatical analysis, compilation and execution. 4.PHP can be combined with MySQL for advanced applications such as user registration systems. 5. When debugging PHP, you can use functions such as error_reporting() and var_dump(). 6. Optimize PHP code to use caching mechanisms, optimize database queries and use built-in functions. 7
The Enduring Relevance of PHP: Is It Still Alive?
Apr 14, 2025 am 12:12 AM
PHP is still dynamic and still occupies an important position in the field of modern programming. 1) PHP's simplicity and powerful community support make it widely used in web development; 2) Its flexibility and stability make it outstanding in handling web forms, database operations and file processing; 3) PHP is constantly evolving and optimizing, suitable for beginners and experienced developers.
Explain the match expression (PHP 8 ) and how it differs from switch.
Apr 06, 2025 am 12:03 AM
In PHP8, match expressions are a new control structure that returns different results based on the value of the expression. 1) It is similar to a switch statement, but returns a value instead of an execution statement block. 2) The match expression is strictly compared (===), which improves security. 3) It avoids possible break omissions in switch statements and enhances the simplicity and readability of the code.
