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28-584: Java view technologies and frameworks are web-based software libraries that provide the user interface , or " view-layer ", of Java web applications . Such application frameworks are used for defining web pages and handling the HTTP requests (clicks) generated by those web pages. As a sub-category of web frameworks , view-layer frameworks often overlap to varying degrees with web frameworks that provide other functionality for Java web applications. Java view-layer frameworks often claim to support some or all of
56-585: A web browser . Web applications emerged during the late 1990s and allowed for the server to dynamically build a response to the request, in contrast to static web pages . Web applications are commonly distributed via a web server . There are several different tier systems that web applications use to communicate between the web browsers, the client interface, and server data. Each system has their own uses as they function in different ways. However, there are many security risks that developers must be aware of during development; proper measures to protect user data
84-403: A development team to focus on the parts of their application which are unique to their goals without having to resolve common development issues such as user management. In addition, there is potential for the development of applications on Internet operating systems , although currently there are not many viable platforms that fit this model. Dynamic HTML Dynamic HTML , or DHTML ,
112-469: A document without adding or removing elements. This helps keep documents small and the scripts that manipulate the document fast. The object model provides programmatic access to styles. This means you can change inline styles on individual elements and change style rules using simple JavaScript programming. Inline styles are CSS style assignments that have been applied to an element using the style attribute. You can examine and set these styles by retrieving
140-421: A web browser tab but later can run completely offline and can be launched without entering the app URL in the browser. Traditional PC applications are typically single-tiered, residing solely on the client machine. In contrast, web applications inherently facilitate a multi-tiered architecture. Though many variations are possible, the most common structure is the three-tiered application. In its most common form,
168-653: A web page's structure, which in turn affect the look, behavior, and functionality of otherwise "static" HTML content after the page has been fully loaded and during the viewing process. Thus the dynamic characteristic of DHTML is the way it functions while a page is viewed, not in its ability to generate a unique page with each page load. By contrast, a dynamic web page is a broader concept, covering any web page generated differently for each user, load occurrence, or specific variable values. This includes pages created by client-side scripting and ones created by server-side scripting (such as PHP , Python , JSP or ASP.NET ) where
196-472: Is a term which was used by some browser vendors to describe the combination of HTML , style sheets and client-side scripts ( JavaScript , VBScript , or any other supported scripts) that enabled the creation of interactive and animated documents. The application of DHTML was introduced by Microsoft with the release of Internet Explorer 4 in 1997. DHTML (Dynamic HTML) allows scripting languages, such as JavaScript, to modify variables and elements in
224-439: Is broken down into a more fine-grained model. Another benefit would be to add an integration tier, which separates the data tier and provides an easy-to-use interface to access the data. For example, the client data would be accessed by calling a "list_clients()" function instead of making an SQL query directly against the client table on the database. This allows the underlying database to be replaced without making any change to
252-507: Is the product of three related and complementary technologies: HTML, Cascading Style Sheets (CSS), and JavaScript . To allow scripts and components to access features of HTML and CSS, the contents of the document are represented as objects in a programming model known as the Document Object Model (DOM). The DOM API is the foundation of DHTML, providing a structured interface that allows access and manipulation of virtually anything in
280-532: Is vital. Web applications are often constructed with the use of a web application framework . Single-page and progressive are two approaches for a website to seem more like a native app. The concept of a "web application" was first introduced in the Java language in the Servlet Specification version 2.2, which was released in 1999. At that time, both JavaScript and XML had already been developed, but
308-484: The Document Object Model (DOM) and page style. The combination of HTML, CSS, and JavaScript offers ways to: A less common use is to create browser-based action games. Although a number of games were created using DHTML during the late 1990s and early 2000s, differences between browsers made this difficult: many techniques had to be implemented in code to enable the games to work on multiple platforms. Browsers have since then converged toward web standards , which has made
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#1733085894224336-570: The XMLHttpRequest object had only been recently introduced on Internet Explorer 5 as an ActiveX object. Beginning around the early 2000s, applications such as " Myspace (2003), Gmail (2004), Digg (2004), [and] Google Maps (2005)," started to make their client sides more and more interactive. A web page script is able to contact the server for storing/retrieving data without downloading an entire web page. The practice became known as Ajax in 2005. In earlier computing models like client-server,
364-420: The model–view–controller design pattern. The Servlet API is the foundation of almost all Java Web View technologies. Servlet provides the basic mechanism for writing Java classes for web applications. Servlets can respond to HTTP requests, create cookies and maintain sessions. Web-based A web application (or web app ) is application software that is created with web technologies and runs via
392-461: The support cost and decreasing productivity . Additionally, both the client and server components of the application were bound tightly to a particular computer architecture and operating system , which made porting them to other systems prohibitively expensive for all but the largest applications. Later, in 1995, Netscape introduced the client-side scripting language called JavaScript , which allowed programmers to add dynamic elements to
420-467: The web server generates content before sending it to the client. DHTML is the predecessor of Ajax and DHTML pages are still request/reload-based. Under the DHTML model, there may not be any interaction between the client and server after the page is loaded; all processing happens on the client side. By contrast, Ajax extends features of DHTML to allow the page to initiate network requests (or 'subrequest') to
448-405: The day-to-day difficulties in cross-browser DOM manipulation, though better standards compliance among browsers has reduced the need for this. Typically a web page using DHTML is set up in the following way: The following code illustrates an often-used function. An additional part of a web page will only be displayed if the user requests it. DHTML is not a technology in and of itself; rather, it
476-436: The design of DHTML games more viable. Those games can be played on all major browsers and in desktop and device applications that support embedded browser contexts. The term "DHTML" has fallen out of use in recent years as it was associated with practices and conventions that tended to not work well between various web browsers. DHTML support with extensive DOM access was introduced with Internet Explorer 4.0 . Although there
504-416: The development process. This includes processes for authentication, authorization, asset handling, input, and logging and auditing. Building security into the applications from the beginning is sometimes more effective and less disruptive in the long run. Writing web applications is simplified with the use of web application frameworks . These frameworks facilitate rapid application development by allowing
532-401: The document. The HTML elements in the document are available as a hierarchical tree of individual objects, making it possible to examine and modify an element and its attributes by reading and setting properties and by calling methods. The text between elements is also available through DOM properties and methods. The DOM also provides access to user actions such as pressing a key and clicking
560-454: The mouse. It is possible to intercept and process these and other events by creating event handler functions and routines. The event handler receives control each time a given event occurs and can carry out any appropriate action, including using the DOM to change the document. Dynamic styles are a key feature of DHTML. By using CSS, one can quickly change the appearance and formatting of elements in
588-425: The other tiers. There are some who view a web application as a two-tier architecture. This can be a "smart" client that performs all the work and queries a "dumb" server, or a "dumb" client that relies on a "smart" server. The client would handle the presentation tier, the server would have the database (storage tier), and the business logic (application tier) would be on one of them or on both. While this increases
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#1733085894224616-463: The processing load for the application was shared between code on the server and code installed on each client locally. In other words, an application had its own pre-compiled client program which served as its user interface and had to be separately installed on each user's personal computer . An upgrade to the server-side code of the application would typically also require an upgrade to the client-side code installed on each user workstation, adding to
644-469: The scalability of the applications and separates the display and the database, it still does not allow for true specialization of layers, so most applications will outgrow this model. Security breaches on these kinds of applications are a major concern because it can involve both enterprise information and private customer data. Protecting these assets is an important part of any web application, and there are some key operational areas that must be included in
672-401: The server even after page load to perform additional actions. For example, if there are multiple tabs on a page, the pure DHTML approach would load the contents of all tabs and then dynamically display only the one that is active, while AJAX could load each tab only when it is really needed. DHTML allows authors to add effects to their pages that are otherwise difficult to achieve, by changing
700-439: The three tiers are called presentation , application and storage . The first tier, presentation, refers to a web browser itself. The second tier refers to any engine using dynamic web content technology (such as ASP , CGI , ColdFusion , Dart , JSP/Java , Node.js , PHP , Python or Ruby on Rails ). The third tier refers to a database that stores data and determines the structure of a user interface. Essentially, when using
728-410: The three-tiered system, the web browser sends requests to the engine, which then services them by making queries and updates against the database and generates a user interface. The 3-tier solution may fall short when dealing with more complex applications, and may need to be replaced with the n-tiered approach; the greatest benefit of which is how business logic (which resides on the application tier)
756-502: The user interface that ran on the client side. Essentially, instead of sending data to the server in order to generate an entire web page, the embedded scripts of the downloaded page can perform various tasks such as input validation or showing/hiding parts of the page. " Progressive web apps ", the term coined by designer Frances Berriman and Google Chrome engineer Alex Russell in 2015, refers to apps taking advantage of new features supported by modern browsers, which initially run inside
784-498: Was a basic dynamic system with Netscape Navigator 4.0 , not all HTML elements were represented in the DOM. When DHTML-style techniques became widespread, varying degrees of support among web browsers for the technologies involved made them difficult to develop and debug . Development became easier when Internet Explorer 5.0+ , Mozilla Firefox 2.0+, and Opera 7.0+ adopted a shared DOM inherited from ECMAScript . Later, JavaScript libraries such as jQuery abstracted away many of
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