Javascript DOM Manipulation
JavaScript DOM manipulation refers to the process of dynamically changing the structure, content, and style of a web page using JavaScript. It involves accessing and modifying the Document Object Model (DOM) of the webpage, allowing developers to add, remove, or modify elements and their attributes. This enables interactive and responsive user interfaces on web applications.
5 Key excerpts on "Javascript DOM Manipulation"
eBook - ePub- Mike McGrath(Author)
- 2020(Publication Date)
- In Easy Steps Limited(Publisher)
...‘ <br> ’ Then, add statements to create buttons in the paragraphs info.innerHTML += ‘ <button onclick=”history.back()”>Back</button> ’ info.innerHTML += ‘<button onclick=”history.forward()”>Forward</button>’ Save the HTML document and JavaScript script file in the same folder, then clear your browser’s history To clear the browser history in the Google Chrome browser, click the button, then select More tools, Clear browsing data, and click the Clear data button. Open the first page to see the initial history length is 1 Click a link to load the third page and see the history length increase to 2 Click the Back button to return to the first page but see the history length remain the same as 2 The URLs are stored in the history object array elements in a protected manner so they cannot be retrieved as strings. In this example, each URL only gets added to the history array when moving to a different page by clicking on a link. The back(), forward(), and go() methods simply select an element in the history array so do not change its length property. Summary • The Document Object Model (DOM) is a hierarchical tree representation of all components of a web page. • The window object is the top level in the DOM hierarchy and has properties describing the browser window. • The screen object is a child of the window object and has properties describing the screen dimensions and color depth. • The window object has scrollBy() and scrollTo() methods and scrollX and scrollY properties that specify the scroll position. • Dialog messages can be displayed using the window object’s alert(), confirm(), and prompt() methods. • A pop-up window can be created using the window object’s open() method, but may be obstructed by a pop-up...
eBook - ePub- David Karlins, Doug Sahlin(Authors)
- 2012(Publication Date)
- For Dummies(Publisher)
...JavaScript J avaScript is the main source of interactivity and animation in web pages. And of even greater value, it helps visitors interact with objects. They can click a button, scroll a drop-down menu, choose an option from a drop-down menu, and so on — all user-initiated events trigger an action. That action might be launching a slideshow, or opening a new browser window, or a form being validated (the data a user enters is tested before that data is sent to a server). As such, JavaScript is the third leg of the basic building blocks of modern, inviting, dynamic websites, along with HTML (which we cover in Book III, and throughout this minibook) and CSS (which we cover in Book IV). Understanding the Role of JavaScript As you peruse the web to identify the source of various content you want to include in your site, train your brain (and eye) to identify JavaScript objects. You’ll find them everywhere. For example, basic fly-out menus, like the one in Figure 1-1 from eBay, are typically created with JavaScript. Drop-down menus and JavaScript There are other techniques for creating animated drop-down menus. For example, some are created using only CSS (style sheets). But JavaScript drop-down menus are the most widely implemented, powerful, and accessible in a wide variety of browsing environments. The JavaScript code that makes drop-down menus work is stored in files with a.js filename extension. If you look at the source code for a website that includes JavaScript, you most likely won’t see the hundreds or thousands of lines of JavaScript code that make drop-down menus and other animated, interactive elements do their thing...
eBook - ePub- Sean McManus(Author)
- 2014(Publication Date)
- In Easy Steps Limited(Publisher)
...8 JavaScript for interactive pages JavaScript enables you to make your web pages interactive. You can check that forms have been completed correctly, update the screen with text or photos; display randomly chosen special offers; and add sophisticated animation and formatting effects to your pages. In this chapter, you’ll learn the basics and discover some handy code you can adapt for your website. What is JavaScript? How to add JavaScript Creating functions Responding to user actions Showing and hiding content How it works Adding a toggle routine Simple form validation Checking text boxes More advanced form tests Customizing by date Opening new windows Adding random content Adding a photo slideshow Saving time with jQuery 2 quick jQuery examples What is JavaScript? While HTML is used to describe the structure of your content, and CSS lets you describe its appearance, JavaScript gives you the power to make the computer perform actions. It is a simple programming language that you can use to make your web page interactive. For security reasons, JavaScript is limited to working within the browser. That means that it can’t interfere with the website visitor’s computer, and access the hard disk, for example. You can, for example: • Update the screen contents after the page has downloaded. You might add new information that has become available since the web page first downloaded, or might show additional information that the user requests. Webmail service Gmail uses JavaScript to show you new messages that come in, without you having to refresh the web page, for example. • Make it easier for visitors to use forms by checking for any errors before the form information is sent to the server. You can provide immediate feedback so that users don’t waste time waiting for the server to respond. • Hide or reveal web page content...
eBook - ePubComputer and Cyber Security
Principles, Algorithm, Applications, and Perspectives
- Brij B. Gupta, Brij B. Gupta(Authors)
- 2018(Publication Date)
- Auerbach Publications(Publisher)
...The DOM is platform-independent, and nodes of every document are organized in a tree structure, and this type of tree representation of HTML and XML objects is called DOM Trees. The node in a DOM tree can have several child nodes, and these nodes are called siblings. The DOM trees can be generated using DOM Tree generator, and these trees can be compared to verify the addition of malicious scripts in web pages. Figure 16.9 displays a detailed algorithm of DOM tree generation. For each web page, extract HTML tags and store them to new_Tag variable. Create a set of all HTML tags into a Tag_Log. Push first tag to a stack, and add it to first node of tree and root points to that node. Run a loop till stack is not empty, and every time extract a new tag, and store it to a temp variable. If the tag is opening tag, then retrieve size of stack in variable n, and insert temp to Tag_Log. Crawl the DOM tree to the position where node is to be inserted. Add temp to this position, and push temp to stack. If the tag is closing tag then, pop the node from stack. Figure 16.9 Algorithm of DOM tree generation. 16.2.3.5 Attack Vector Injection Attack vectors are the JavaScript codes which, if injected to injection points, may cause malicious behavior in web page. There are many attack vectors, and new attack vectors are introduced very frequently. The existing attack vectors are stored in malicious data warehouse, and these can be used wherever required. When injected to web page, the attack vectors cause malicious nature if the web page is not immune to these types of attacks, i.e., the attack vectors are not processed before using them as an input in web pages. 16.2.3.6 Script Nodes Extractor Script nodes are the nodes in DOM trees which contain the JavaScript content and may also contain malicious data, so it needs to be sanitized...
eBook - ePubOnline Journalism
Principles and Practices of News for the Web
- Jim Foust(Author)
- 2017(Publication Date)
- Routledge(Publisher)
...Once you have placed the image, you can make various formatting changes to it using the Properties window. Video clips, audio clips and multimedia elements are placed similarly, using various options under Dreamweaver’s Insert menu. USING JAVASCRIPT FOR INTERACTIVITY A s discussed, JavaScript is a computer scripting language designed to inter. face with HTML to provide greater interactivity. This occurs through the use of client-side applications, programming for HTML documents that is executed on the end-user’s (the client, in the client-server model) device. One of the main purposes of client-side JavaScript is to provide a greater level of interactivity on individual Web pages than can be accomplished using straight HTML, even HTML 5. Server-side applications, as the name implies, reside on the server and are executed on the server. Server-side apps can provide even broader capabilities for the actual creation of Web pages; a content management system, as discussed later in this chapter, can in fact be thought of as a server-side application. JavaScript is used only for client-side programming; other languages, such as Java 1, ASP, Perl and PHP, are used for server-side programming. It is beyond the scope of this book to provide a tutorial on server-side application development or, for that matter, to provide a comprehensive tutorial on client-side JavaScript. However, this section will provide a brief overview of how JavaScript can be used to add simple interactivity to a Web page. JavaScript is text-based so—like HTML—it can be written using a simple text editor or an authoring program. Depending on the example, JavaScript programming can reside in either the <head> or <body> section of an HTML document or as a separate JavaScript file (which normally uses the file extension “.j s”). JavaScript is object-oriented, meaning programs are built using objects—documents, text fields, buttons, graphics or other elements...
