什麼是網絡瀏覽器
本站小編爲大家介紹了網絡瀏覽器，希望對你有幫助哦!
Google Inc.'s move to offer its own Web browser begs a question about a technology that most people now take for granted: What exactly is a Web browser?
The short answer is that it is a piece of software that takes us where we want to go, whether to buy a pair of pants or call up a bus schedule. To understand what a browser really does, though, it helps to understand why it was invented.
Computers were once isolated calculation engines. A user walked up to them, inserted a stack of punch cards or pushed some buttons, and waited for an answer. Later users could interact with a specific system using terminals sold by each computer maker, a phase followed by networks that could connect different kinds of computers run by individual organizations.
In the 1970s, researchers agreed on a set of specifications to send packets between those dissimilar systems -- akin to the address scheme the post office uses to route letters. Thus was born the Internet.
But viewing information on someone else's computer still wasn't easy. For one thing, the information might be stored in a database or other proprietary software that varied among organizations. Tim Berners-Lee, the man credited with inventing the Web, wanted to break down those barriers.
He built on a technology known as hypertext -- the notion of establishing links to connect any concept, or document, to any other. That required developing and popularizing three sets of rules for creating and exchanging documents.
One is hypertext transfer protocol, or HTTP, which establishes specifications for linking documents. Another is an address scheme for finding documents, known as a universal resource locator, or URL. Third is a way to create documents in a consistent format, known as hypertext markup language, or HTML.
But there was still one key element missing: a piece of desktop software to display documents created using HTML, and respond to the communications instructions based on HTTP and URL. So Mr. Berners-Lee created the first browser, a type of program that would later be refined by Netscape Communications Corp., Microsoft Corp. and others.
Today's browsers have been updated to do additional tricks. By using small programs, known as plug-ins, they can allow users to view videos and animations.
But browsers still must manage the more basic chores of displaying documents and navigating between them. When a user clicks on a link on a Web page -- or types a URL into the address line and hits return -- the browser sends a request for information that is converted into data packets and sent out to the Internet.
The request is routed through organizations that manage directories of domain names, and store numerical addresses associated with those names. Once that request reaches the server with that address, it responds by sending a new Web page that bounces back around the Internet to pop up on the user's browser.
谷歌(Google Inc.)計劃推出自主開發的網絡瀏覽器;但這並不意味着人人都瞭解這項大家都習以爲常的技術。那麼，究竟什麼是網絡瀏覽器呢?
簡單的說，網絡瀏覽器就是一款軟件，能帶我們去想去的網站，無論是去買條褲子還是查詢公交時刻表。不過，爲了理解網絡瀏覽器的真正用途，我們有必要回顧下瀏覽器的誕生歷史。
最初，電腦是孤立的運算機器。使用者打開機器，插入一張穿孔卡片或按下某些按鍵，然後等待機器給出一個答案。後來，使用者可以使用電腦製造商出售的終端，通過一個特殊系統與機器進行互動;接下來出現了電腦網絡，它能夠將各單獨組織運行的各種電腦連接起來。
在20世紀70年代，研究人員確定了一系列標準，得以在不同系統之間發送信息包──這類似於郵局發送信件的地址系統。互聯網由此誕生了。
不過，瀏覽他人電腦上的信息仍非易事。首先，信息可能存儲在數據庫，或其他所有權軟件中，而各組織所採用的又各不相同。Web之父蒂姆•伯納斯•李(Tim Berners-Lee)當時希望能夠打破這些障礙。
他利用一種稱爲超文本的技術，提出了在任何概念和文件之間建立連接的想法。由此發展並推廣了三套技術標準，用於創建與交換文件。
其中之一就是超文本傳輸協議，即HTTP，爲文件連接確定了標準。另一套標準是統一資源定位符，即URL，用於尋找文件的地址系統。第三套標準是超文本置標語言，即HTML，以一致的格式創建文件。
不過，我們還需要一個關鍵要素：一個可以顯示以HTML標準創建的文件、並可以響應基於HTTP與URL標準通信指令的電腦軟件。因此，伯納斯•李發明了第一個瀏覽器;在這個基礎上，Netscape Communications Corp.、微軟(Microsoft Corp.)以及其他公司後來紛紛研發了各自的瀏覽器軟件。
如今的瀏覽器已經過升級，可以進行更多的任務。通過使用俗稱插件的小程序，用戶可以通過瀏覽器觀看視頻和動畫。
不過瀏覽器仍然必須滿足最基本的顯示文件和瀏覽功能。當用戶點擊網頁上的鏈接時，或是在地址欄輸入URL網址然後點擊回車，瀏覽器就會發送一條相應的信息請求，這些信息已被轉化爲數據包併發送到了互聯網上。
這一請求信息要途經管理域名地址錄、並儲存這些域名相關地址的組織。一旦信息請求抵達目的服務器，服務器就會發送一個新的網頁，沿着互聯網回覆到用戶的瀏覽器上。
