Visual Basic program that finds. Their method crawls web pages with high PageRank from different. Such software can be used to span multiple Web forms across multiple Websites. Open Search Server is a search engine and web crawler software release.
How does the Internet work. Introduction. Every so often, you get offered a behind- the- scenes look at the cogs and fan belts behind the action. In this part of the Web Standards Curriculum we'll usher you behind the scenes of one of the hottest technologies that you might already be familiar with: the World Wide Web. When we sing we begin with Do Re Mi. In this article I will briefly look at how computers actually communicate, then go on to look at the different languages that go together to create the web pages that make up the Web. When it comes to the World Wide Web, most pages are written using the same language, HTML, which is passed around using a common protocol . HTTP is the common internet language (dialect, or specification), allowing a Windows machine, for example, to sing in harmony with a machine running the latest and greatest version of Linux (Do Re Mi!). Through the use of a web browser, a special piece of software that interprets HTTP and renders HTML into a human- readable form, web pages authored in HTML on any type of computer can be read anywhere, including telephones, PDAs and even popular games consoles. HTTP lays out these ground rules for the Internet. Because of HTTP, a client machine (like your computer) knows that it has to be the one to initiate a request for a web page; it sends this request to a server. A server is a computer where web sites reside . There are some numbered steps below for you to work along with, so I can demonstrate some of the concepts to you more effectively. Open a browser now, and type this URL and press Enter/Return (or follow the above link) to go to the Apple homepage. For example, the IP address of http: //www. This is because people are better at remembering words than long strings of numbers. The system that makes this work is called DNS, which is a comprehensive automatic directory of all of the machines connected to the Internet. When you punch http: //www. IP address. There are a literally millions of machines connected to the Internet, and not every DNS server has a listing for every machine online, so there. If all goes well, the server sends a short message back to the client with a message saying that everything is okay (see Figure 1,) followed by the web page itself. This type of message is contained in an HTTP header. Try it with a few different fake page addresses and you. This is because some web developers have just left the web server to return their default error pages, and others have coded custom error pages to appear when a non- existent page is returned. This is an advanced technique that won. You are always accessing actual files, but sometimes the web developer has set up the web server to not display the file names in the URL . They are grouped these into 4 types . When a plain text file is encountered on the Internet, the browser will just display it as is, without any processing involved. You often still get plain text files on university sites. Typical web pages provide. Other ways of making a web page is to download specialized software.There are a ton of advantages to separating the structure from the style, and we. To demonstrate the power of HTML and CSS used together, Figure 2 shows some plain HTML on the left, with no formatting added to it at all, while on the right you can see exactly the same HTML with some CSS styles applied to it. You can write programs in Java. Script that will run in the web browser, requiring no special software to be installed. Java. Script allows you to add powerful interactivity and dynamic features to your web site, but it has its limitations, which brings us to server- side programming languages, and dynamic web pages. These are all examples of server- side web technologies, which can be used to create web pages with sections that change depending on variable values given to the page on the server, before the page is sent to the web browser to be displayed. For example, a movie listings page could pull movie information from a database, and display different movie information for different days, weeks or months. For example. If you encounter a Word document, Excel file, PDF, compressed file (ZIP, or RAR), complex image file such as a Photoshop PSD, or another file that the browser doesn. Both of these usually have similar results, except that the latter will cause the file to be downloaded and then opened by an application that does understand it, if one is installed. If not, you will usually be given a link to install the required plugin, or the file will download and look for a desktop application to run it. Dynamic Web Sites. So what are static and dynamic web sites, and what is the difference between the two? Similar to a box of chocolates, it. This different information is kept in a database, which pulls up the relevant information when requested, and gives it to the web server to insert into the dynamic page. Whereas normal static HTML files are saved with a file extension of . HTML, and are saved with special file extensions to tell the web server that they need extra processing before they are sent to the client (such as having the data inserted from the database). PHP files for example usually have a . In the end, all of these languages have pretty much the same capabilities, like talking to databases, validating information entered into forms, etc., but they do things slightly differently, and have some advantages and disadvantages. It all boils down to what suits you best. This article really just scratches the surface of a lot of the topics covered, but it is useful as it puts them all in perspective, showing how they all relate and work together. There is still a lot left to learn about the actual language syntax that makes up HTML, CSS and Java. Script, and this is where we. Access some of these and have a think about how your computer displays them to you. Like the original, it is published under the Creative Commons Attribution, Non Commercial - Share Alike 2.
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