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Canonical Link Element
A canonical link element is an HTML element that helps webmasters prevent duplicate content issues in search engine optimization by specifying the "canonical" or "preferred" version of a web page. It is described in RFC 6596, which went live in April 2012. Purpose A major problem for search engines is to determine the original source for documents that are available on multiple URLs. Content duplication can happen in many ways, including: * Duplication due to -parameters * Duplication with multiple URLs due to CMS * Duplication due to accessibility on different hosts/protocols * Duplication due to print versions of websites Duplicate content issues occur when the same content is accessible from multiple URLs. For example, would be considered by search engines to be an entirely different page from , even though both URLs may reference the same content. In February 2009, Google, Yahoo and Microsoft announced support for the canonical link element, which can be inserted into t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HTML Element
An HTML element is a type of HTML (HyperText Markup Language) document component, one of several types of HTML nodes (there are also text nodes, comment nodes and others). The first used version of HTML was written by Tim Berners-Lee in 1993 and there have since been many versions of HTML. The most commonly used version is HTML 4.01, which became official standard in December 1999. An HTML document is composed of a tree of simple HTML nodes, such as text nodes, and HTML elements, which add semantics and formatting to parts of document (e.g., make text bold, organize it into paragraphs, lists and tables, or embed hyperlinks and images). Each element can have HTML attributes specified. Elements can also have content, including other elements and text. Concepts Elements vs. tags As is generally understood, the position of an element is indicated as spanning from a start tag and is terminated by an end tag. This is the case for many, but not all, elements within an HTML docume ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spamdexing
Spamdexing (also known as search engine spam, search engine poisoning, black-hat search engine optimization, search spam or web spam) is the deliberate manipulation of search engine indexes. It involves a number of methods, such as link building and repeating unrelated phrases, to manipulate the relevance or prominence of resources indexed, in a manner inconsistent with the purpose of the indexing system."Word Spy - spamdexing" (definition), March 2003, webpagWordSpy-spamdexing. Spamdexing could be considered to be a part of search engine optimization, although there are many search engine optimization methods that improve the quality and appearance of the content of web sites and serve content useful to many users. Overview Search engines use a variety of algorithms to determine relevancy ranking. Some of these include determining whether the search term appears in the body text or URL of a web page. Many search engines check for instances of spamdexing and will remove susp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
URL Normalization
URI normalization is the process by which URIs are modified and standardized in a consistent manner. The goal of the normalization process is to transform a URI into a normalized URI so it is possible to determine if two syntactically different URIs may be equivalent. Search engines employ URI normalization in order to correctly rank pages that may be found with multiple URIs, and to reduce indexing of duplicate pages. Web crawlers perform URI normalization in order to avoid crawling the same resource more than once. Web browsers may perform normalization to determine if a link has been visited or to determine if a page has been cached. Web servers may also perform normalization for many reasons (i.e. to be able to more easily intercept security risks coming from client requests, to use only one absolute file name for each resource stored in their caches, named in log files, etc.). Normalization process There are several types of normalization that may be performed. Some of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Context Menu
A context menu (also called contextual, shortcut, and pop up or pop-up menu) is a menu in a graphical user interface (GUI) that appears upon user interaction, such as a right-click mouse operation. A context menu offers a limited set of choices that are available in the current state, or context, of the operating system or application to which the menu belongs. Usually the available choices are actions related to the selected object. From a technical point of view, such a context menu is a graphical control element. History Context menus first appeared in the Smalltalk environment on the Xerox Alto computer, where they were called ''pop-up menus''; they were invented by Dan Ingalls in the mid-1970s. Microsoft Office v3.0 introduced the context menu for copy and paste functionality in 1990. Borland demonstrated extensive use of the context menu in 1991 at the Second Paradox Conference in Phoenix Arizona. Lotus 1-2-3/G for OS/2 v1.0 added additional formatting options in 1991 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Browser Extension
A browser extension is a small software module for customizing a web browser. Browsers typically allow a variety of extensions, including user interface modifications, cookie management, ad blocking, and the custom scripting and styling of web pages. Plug-ins Browser plug-ins are a separate type of module. The main difference is that extensions are distributed as source code, while plug-ins are distributed as executables (i.e. object code). Plug-ins are no longer supported by the major browsers, but extensions are widely used. The most popular browser, Google Chrome, has over 100,000 extensions available but stopped supporting plug-ins in 2020. History Internet Explorer was the first major browser to support extensions, with the release of version 4 in 1999. Firefox has supported extensions since its launch in 2004. Opera began supporting extensions in 2009, and both Google Chrome and Safari did so the following year. Microsoft Edge added extension support in 2016. API confo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Usability
Usability can be described as the capacity of a system to provide a condition for its users to perform the tasks safely, effectively, and efficiently while enjoying the experience. In software engineering, usability is the degree to which a software can be used by specified consumers to achieve quantified objectives with effectiveness, efficiency, and satisfaction in a quantified context of use. The object of use can be a software application, website, book, tool, machine, process, vehicle, or anything a human interacts with. A usability study may be conducted as a primary job function by a ''usability analyst'' or as a secondary job function by designers, technical writers, marketing personnel, and others. It is widely used in consumer electronics, communication, and knowledge transfer objects (such as a cookbook, a document or online help) and mechanical objects such as a door handle or a hammer. Usability includes methods of measuring usability, such as needs analysis and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clean URL
Clean URLs, also sometimes referred to as RESTful URLs, user-friendly URLs, pretty URLs or search engine-friendly URLs, are URLs intended to improve the usability and accessibility of a website or web service by being immediately and intuitively meaningful to non-expert users. Such URL schemes tend to reflect the conceptual structure of a collection of information and decouple the user interface from a server's internal representation of information. Other reasons for using clean URLs include search engine optimization (SEO), conforming to the representational state transfer (REST) style of software architecture, and ensuring that individual web resources remain consistently at the same URL. This makes the World Wide Web a more stable and useful system, and allows more durable and reliable bookmarking of web resources. Clean URLs also do not contain implementation details of the underlying web application. This carries the benefit of reducing the difficulty of changing the imple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperlink
In computing, a hyperlink, or simply a link, is a digital reference to data that the user can follow or be guided by clicking or tapping. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text with hyperlinks. The text that is linked from is known as anchor text. A software system that is used for viewing and creating hypertext is a ''hypertext system'', and to create a hyperlink is ''to hyperlink'' (or simply ''to link''). A user following hyperlinks is said to ''navigate'' or ''browse'' the hypertext. The document containing a hyperlink is known as its source document. For example, in an online reference work such as Wikipedia or Google, many words and terms in the text are hyperlinked to definitions of those terms. Hyperlinks are often used to implement reference mechanisms such as tables of contents, footnotes, bibliographies, indexes, letters, and glossaries. In some hypertext, hyperlinks can be bidirectional: they can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stack Overflow
In software, a stack overflow occurs if the call stack pointer exceeds the stack bound. The call stack may consist of a limited amount of address space, often determined at the start of the program. The size of the call stack depends on many factors, including the programming language, machine architecture, multi-threading, and amount of available memory. When a program attempts to use more space than is available on the call stack (that is, when it attempts to access memory beyond the call stack's bounds, which is essentially a buffer overflow), the stack is said to ''overflow'', typically resulting in a program crash. Causes Infinite recursion The most-common cause of stack overflow is excessively deep or infinite recursion, in which a function calls itself so many times that the space needed to store the variables and information associated with each call is more than can fit on the stack. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HTTP Header
The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, where hypertext documents include hyperlinks to other resources that the user can easily access, for example by a mouse click or by tapping the screen in a web browser. Development of HTTP was initiated by Tim Berners-Lee at CERN in 1989 and summarized in a simple document describing the behavior of a client and a server using the first HTTP protocol version that was named 0.9. That first version of HTTP protocol soon evolved into a more elaborated version that was the first draft toward a far future version 1.0. Development of early HTTP Requests for Comments (RFCs) started a few years later and it was a coordinated effort by the Internet Engineering Task Force (IETF) and the World Wide Web Consortium (W3C), with work later moving to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semantics (computer Science)
In programming language theory, semantics is the rigorous mathematical study of the meaning of programming languages. Semantics assigns computational meaning to valid strings in a programming language syntax. Semantics describes the processes a computer follows when executing a program in that specific language. This can be shown by describing the relationship between the input and output of a program, or an explanation of how the program will be executed on a certain platform, hence creating a model of computation. History In 1967, Robert W. Floyd publishes the paper ''Assigning meanings to programs''; his chief aim is "a rigorous standard for proofs about computer programs, including proofs of correctness, equivalence, and termination". Floyd further writes: A semantic definition of a programming language, in our approach, is founded on a syntactic definition. It must specify which of the phrases in a syntactically correct program represent commands, and what conditions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Web Crawler
A Web crawler, sometimes called a spider or spiderbot and often shortened to crawler, is an Internet bot that systematically browses the World Wide Web and that is typically operated by search engines for the purpose of Web indexing (''web spidering''). Web search engines and some other websites use Web crawling or spidering software to update their web content or indices of other sites' web content. Web crawlers copy pages for processing by a search engine, which indexes the downloaded pages so that users can search more efficiently. Crawlers consume resources on visited systems and often visit sites unprompted. Issues of schedule, load, and "politeness" come into play when large collections of pages are accessed. Mechanisms exist for public sites not wishing to be crawled to make this known to the crawling agent. For example, including a robots.txt file can request bots to index only parts of a website, or nothing at all. The number of Internet pages is extremely large; ev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
