Web topic 26 browser compatibilty and security


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Web topic 26 browser compatibilty and security

  1. 1. Web Authoring Topic 26 –Browser Compatibility & Security
  2. 2. ObjectivesStudents should able to:1. Describe the necessity of performing a browser compatibility test.2. Follow procedures to ensure the browser compatibility of websites.
  3. 3. Browser CompatibilityBrowser testing is necessary becausedifferent web browsers render HTML andCSS code differently.If you’ve tried using different Web browsersto surf online, you’ve probably noticed thatthe same sites look a little differentdepending on which browser you’re using.
  4. 4. Browser CompatibilityThat is because page display variesaccording to browser compatibility.Browser compatibility is the ability of theWeb browser to properly interpret thehypertext markup language (HTML) thatrenders Web pages.
  5. 5. Browser CompatibilityMost sites are designed to look correct inMicrosoft’s Internet Explorer, because it isbelieved to be the most ubiquitousbrowser.However, if you are a Web designer, yourtask is to code a site for maximumbrowser compatibility so that the pageslook correct in other popular browserssuch as FireFox, Safari, Google Chrome,etc.
  6. 6. Browser CompatibilityBrowser compatibility creates potentialheadaches for webmasters.As newer popular scripting languagescreate flashy Web pages, older browsersmay not understand the new code.For security reasons, many people disablescripting languages in their Web browsers,reducing browser compatibility.
  7. 7. Browser CompatibilityAside from the difference in browsers,another factor that plays into browsercompatibility is whether the surfer is usinga standard PC and Windows, Linux, or aMac computer.The same browser will render the pages alittle differently from each of theseplatforms.
  8. 8. Browser CompatibilityWhy browser testing is important?A web browser is a program that rendersHTML, CSS and Javascript files accordingto a set of rules built into the application.Although web browser manufacturers usethe recommended guidelines of the WorldWide Web Consortium’s specifications forHTML and CSS, they can interpret theserules as required for their own purposes.
  9. 9. Browser CompatibilityAre web pages required to look the samein all browsers? In the case of technical considerations, you must determine whether you could achieve your goal of making a web page look the same. For example, the earliest browsers, such as Internet Explorer 3 or Netscape 3, do not support cascading style sheets.
  10. 10. Browser CompatibilityAre web pages required to look the samein all browsers? In the case of time/budget considerations, you might find technical solutions to make your pages look the same, but if it takes you more time than you have allotted to identify and fix the problem you should determine whether the solution is worth it.
  11. 11. Browser CompatibilityAttempting to make web pages look thesame in multiple browsers is not asimportant due to several reasons:- People browse the web in different ways.- Monitor resolution. A website on a 17-inch monitor never looks the same as on a27-inch monitor.
  12. 12. Browser Compatibility- Text resizing. Users can override thepage layout by increasing or decreasingtext size.- Mobile devices, which represent agrowing proportion of web browsers.- Client expectations, as clients are quiteoften less technically oriented than theweb designer.
  13. 13. Browser CompatibilityChoose the level browser of browsersupport you wantThe level of browser use partially accountsfor your decision to support it. The choiceof which browsers to support becomesmore difficult with more recent browsers.
  14. 14. Browser CompatibilityBrowser StatisticsLocating an accurate number of the webbrowsers currently in use today is difficult.Individual websites can gather accurateinformation on their user’s browserversion. Visit to some of the sites listedbelow for an accurate estimate. www.statowl.com www.w3schools.com/browsers/browsers_stats.asp
  15. 15. Browser CompatibilityTools to identify browser problemsThe first step in testing your page design isto view it in the desired browser.However, this is not always easy, forvarious reasons.
  16. 16. Browser Compatibility • You might not have access to thebrowser, which is a common problemwhen testing for cross-browsercompatibility. Cross-browser refers to theability for a website to support all the webbrowsers.
  17. 17. Browser Compatibility• Different windows operating systemmight not allow multiple versions ofInternet Explorer to be installed on thesame system.A common solution is to have access to aseparate computer.Many web designers invest in aninexpensive computer mainly used fortesting.
  18. 18. Browser CompatibilityHowever, this option may not be practicalfor several reasons: • Inefficiency. There might be a time lag involved in continuously changing computers. • The debugging process involvesmaking many small changes. It couldbecome tedious to change computersafter every change.
  19. 19. Browser CompatibilityVirtualization solutions for WindowsIf a Windows computer is your primarydevice and you need to test your designson a Mac, you will need a separatecomputer.You could have Windows 7 with a modernbrowser as your primary system, and avirtual machine that runs Windows XPwith Internet Explorer 6.
  20. 20. Browser CompatibilityWindows Virtual PCWindows virtual PC is Microsoft’s nativevirtualization tool that allows you to installone or more virtual machines on yoursystem.You need sufficient system resources, suchas hard-drive space and memory, to makethis a viable option.
  21. 21. Browser CompatibilityBrowser compatibility applicationsAn alternative is to use a browser testingapplication or service whose only job is totest web pages. Although the detailsdiffer, the basic concept is the same: toprovide “snapshots” of your web pages indifferent browsers.
  22. 22. Browser CompatibilityDreamweaver CS5Dreamweaver CS5 has a new feature thatwill help you track down the mostcommon bugs – and give you the fix forthem as well. It is called Check BrowserCompatibility and it is accessed throughthe Check Page icon in the Standardtoolbar.
  23. 23. Browser CompatibilityAdobe BrowserLabBrowserLab lets you preview your page ina number of different browsers andplatforms, so you are not limited to Macor PC. The basic steps are to enter the URLof the page you would like to preview togenerate a screenshot of the page. Youcan then compare the screenshots if youdefine multiple browsers.
  24. 24. Browser CompatibilityMicrosoft SuperPreviewSuperPreview is a Windows platform thatonly uses the browsers installed on a localsystem, but it also has a network featuresimilar to BrowserLab to let you view yourpage using Safari on OS X.SuperPreview will not solve the layoutissues, but it helps you to easily identifythem.
  25. 25. Web Application SecurityCommon vulnerabilitiesSome of the vulnerabilities youll belooking for is:By far the most popular: cross-sitescripting (XSS). XSS results from maliciousscripts being injected into a Web site.
  26. 26. Web Application SecurityCommon vulnerabilitiesSQL injection is the second most popularvulnerability, primarily because of thegrowing dependence Web sites have ondatabases.
  27. 27. Web Application SecurityCommon vulnerabilitiesSQL injection is actually quite simple:By finding a Web site that connects to adatabase, malicious hackers execute anSQL query in a place that the developernever intended for the purpose ofbypassing authentication or manipulatingdata.
  28. 28. Web Application SecurityWebScarabWebScarab is first and foremost a proxyused to analyze browser requests andserver replies.In addition to serving as a tool for packetanalysis, you can use it to "fuzz" sites,looking for some of the same exploits asmentioned.