Free practice test , mock test, driving test, interview questions » firefox http://www.skill-guru.com/blog Find free mock and practice test, create and sell tests Mon, 16 Jan 2012 16:53:10 +0000 http://wordpress.org/?v=2.9.2 en hourly 1 Cross domain Scripting comes to haunt again http://www.skill-guru.com/blog/2011/03/06/cross-domain-scripting-comes-to-haunt-again/ http://www.skill-guru.com/blog/2011/03/06/cross-domain-scripting-comes-to-haunt-again/#comments Sun, 06 Mar 2011 18:12:41 +0000 Vinay http://www.skill-guru.com/blog/?p=3908 In my last posts I had talked about Cross domain scripting issue with Firefox and how to solve cross domain scripting issues on tomcat

But looks like the issue has not been completely resolved. I have used the CORS filter solution as we are working on tomcat but have some problems in exception scenarios

Problem Statement:

I am trying to make a call to a REST service and trying to catch an 404 or 200 condition returned by REST and show an appropriate message to user based on error code.

My url in browser is http://localhost:8080/myapp/test.html

The code inside is

<html>
<head>
<script type=”text/javascript” charset=”utf-8″ src=”json2.js”></script>
<script type=”text/javascript” charset=”utf-8″ src=”jquery-1.4.4.min.js”></script>
<script>

function invokeFunction()
{

var myService = null;
if (window.XMLHttpRequest) //for mozilla
{
myService = new XMLHttpRequest();

if ( typeof myService.overrideMimeType != ‘undefined’)
myService.overrideMimeType(‘application/json’);
}
else if (window.ActiveXObject) //for IE
{
myService = new ActiveXObject(“Microsoft.XMLHTTP”);
}

var serviceUrl = “http://127.0.0.1:8080/myapp/webresources/user/1111“;

try{

myService.open(“GET”, serviceUrl , false);
myService.send();

if(myService.status == 404 || myService.status == 0)
{

alert(‘404 >>>>’ +myService.responseText);
}
else if(myService.status == 200)
{

alert(‘200 >>>>’ +myService.responseText);
}

}catch(err){

alert(” Error in REST service “+err.description+’  ‘+myService.status+’ ‘+myService.readyState);
}

}

Now when you look at code above

What happens in Firefox ?

My address in browser specifies localhost and I am making call to 127.0.0.1 and although post numbers are same, Firefox treats it as a cross domain. This would not have worked in FF but since I am using CORS filter, I am getting data if there is user with id 1111.

What happens in IE ?

This works perfectly fine in IE .

How to fix this ?

This will work if you just intend to capture the exception and not much concerned with exception message send by server. But if you have display different error messages to client based on error messages

For now we have wrapped the error messages also as response and return as 200.

]]> http://www.skill-guru.com/blog/2011/03/06/cross-domain-scripting-comes-to-haunt-again/feed/ 0 IE caching Ajax calls http://www.skill-guru.com/blog/2011/03/02/ie-caching-ajax-calls/ http://www.skill-guru.com/blog/2011/03/02/ie-caching-ajax-calls/#comments Thu, 03 Mar 2011 02:02:21 +0000 Vinay http://www.skill-guru.com/blog/?p=3890 If you have been trying to make a REST call from your javascript or jsp page, you might have found that in firefox(FF) and Safari there is a call made to server every time . But this does not happen in IE.

This is the scenario I had

I had script file client.js which was making a rest call to get some data.

First time I could see the results but then with every other subsequent call, there was no change in state, although the data should have changed.

Now this can be fixed by multiple ways

Option 1:

Change the browser settings. To  do this you have to go to

General–Settings>

and change the settings from Automatically to Every Visit to page

This will resolve the issue.

Option 2:

Change from GET to POST

Option 3 :

Add a timestamp at end of url which will looking at which server will think it is a new URL.

I am planning to find some better solution but did not had any luck so far. Once I find anything, will update the post.

Update : Here is the solution using Servlet Filter  Servlet Filter to prevent No Cache

]]> http://www.skill-guru.com/blog/2011/03/02/ie-caching-ajax-calls/feed/ 1 Double submits in Firefox browser http://www.skill-guru.com/blog/2011/02/06/double-submits-in-firefox-browser/ http://www.skill-guru.com/blog/2011/02/06/double-submits-in-firefox-browser/#comments Mon, 07 Feb 2011 04:12:22 +0000 Vinay http://www.skill-guru.com/blog/?p=3791 If you had ever experienced double form submit in your application in Firefox, ,here is the clue

It could be because of the Firebug. For me at least the problem was firebug.

I was on version 3.5.8 of firefox and the version of firebug installed with this version had bug.

I had to upgrade to firefox 3.6 to get latest version of firebug and then this problem did not happen.

Alternatively turn of firebug or any other recent add on you installed and this double form submission problem should go away.

]]> http://www.skill-guru.com/blog/2011/02/06/double-submits-in-firefox-browser/feed/ 1 The 500 ft perspective of website performance http://www.skill-guru.com/blog/2010/09/17/the-500-ft-perspective-of-website-performance/ http://www.skill-guru.com/blog/2010/09/17/the-500-ft-perspective-of-website-performance/#comments Fri, 17 Sep 2010 15:10:32 +0000 Vinay http://www.skill-guru.com/blog/?p=2670 Let us start with this simple questions, What are the engineers at google are obsessed with ?

Answer : Speed

Google instant was the latest delivered in search in which google displays search result as soon as you start punching your keyboard. By predicting your search and showing results before you finish typing, Google Instant can save 2-5 seconds per search.

Google’s spoke person Matt Cutts had also made it clear that the sites which will perform slow , will be penalized.

So what is the next thing web developers around the world will start work towards (They have been working towards it , but now they might get obsessed) ?

Yes you are right . Improve the performance of their website/application.

improve website performance

Ed Robinson co-founder and CEO of Aptimize, posted this excellent article on looking at website optimization with a 500 ft perspective. He says that the average speed of an internet connection was 50Kbps in 1996. In 2010 the average speed of a broadband connection is 3.9Mbps – an increase of over 74 times.  But the size of web pages has also increased manifold , on account of rich graphics and  more data.  He divides optimization into three main categories:

  1. Network Optimization
  2. Website/Application Optimization
  3. Website Acceleration

This diagram spells out the core areas where performance can be impacted

Faster websites

He has re iterated some of the facts that it is not always networks which are to be blamed for poor site performance. It is the application which also has to improve.

Chrome has come out with the fastest java script engine . Firefox was not far behind , coning out with release of JaegerMonkey java script engine which is faster than their earlier release trace monkey.

Then there are YUI guidelines Best Practices for Speeding Up Your Web Site

Previously the performance tuning mean looking into server side code, tuning sql’s and analyzing memory graph. This is still important but there are lot of other variables which have come into play to determine the performance of website.  When optimizing site , one should always consider all these factors and  not solely on one.

]]> http://www.skill-guru.com/blog/2010/09/17/the-500-ft-perspective-of-website-performance/feed/ 1 How to run IE only sites from Linux http://www.skill-guru.com/blog/2010/06/11/how-to-run-ie-only-sites-from-linux/ http://www.skill-guru.com/blog/2010/06/11/how-to-run-ie-only-sites-from-linux/#comments Fri, 11 Jun 2010 21:49:44 +0000 Vinay http://www.skill-guru.com/blog/?p=2367 Sounds stupid ? Why would you want to run IE from Linux ? Why not use Firefox or Chrome ?

But that is not always the scenario.

Reason no 1 : Web designers who use Linux need to test their site on IE . Do not forget IE still commands majority of browser market 59.95%. Can you afford to ignore IE .

Obviously not !

Reason no 2 : Organizations who have created IE only applications 7-10 years back and are now switching to Linux platform , do not want to spend time and money porting the application to new browsers.

So when confronted with this problem what can be done ?

Solution 1 :

If you have windows as your OS then you can use this fantastic plugin IE Tab for Firefox. I have tried this and our UI was pretty heavy bit worked perfectly fine with plugin. I think as of date, the developers are not supporting this plugin so you might not be able to find upgrade for latest version of Firefox.  There are other plugins similar to IE tab in firefox which you wanna try out.

Drawback : This does not work on Linux.

Solution 2:

On linux environment, you can use

a) IE View on Linux This can be achieved by installing WINE.

b) IES4Linux – It is an convenient way to install and run IE 5.0, 5.5, and IE6 (IE7 support is in progress). One difference is that IEs4Linux doesn’t do a full WINE install and configuration, it just does what’s needed to run the different IE versions

IEs4Linux will not be very effective if you have a very heavy UI with lot of controls.

]]> http://www.skill-guru.com/blog/2010/06/11/how-to-run-ie-only-sites-from-linux/feed/ 4 Performance issue in IE 7 java Script Engine http://www.skill-guru.com/blog/2010/03/31/performance-issue-in-ie-7-java-script-engine/ http://www.skill-guru.com/blog/2010/03/31/performance-issue-in-ie-7-java-script-engine/#comments Wed, 31 Mar 2010 23:28:46 +0000 Vinay http://www.skill-guru.com/blog/?p=1935 In one of my earlier post  Performance Improvement with Firefox ,  I had mentioned how we had to switch to firefox for our application response time in IE.  Andres in his post Garbage Collection in IE7 heavily impacted by number of JavaScript objects and string sizes is sharing his experience with performance issue in IE 7 java Script Engine .  One of his key recommendations , Be careful with string allocations and objects in memory -> GC in IE7 performs really badly

There is another presentation by Frank on browser problem in AJAX application in which he used PushToTest TestMaker to drive an Ajax application on IE 6 and 7 and on Firefox 3. to find out why some Selenium tests of Ajax applications were running at 3 minutes while the same test on a different browser took 30 minutes. You can find the details here Browser problems in AJAX applications

]]> http://www.skill-guru.com/blog/2010/03/31/performance-issue-in-ie-7-java-script-engine/feed/ 0 Analyzing web site performance in Firefox with YSlow http://www.skill-guru.com/blog/2010/03/14/analyzing-web-site-performance-with-firefox/ http://www.skill-guru.com/blog/2010/03/14/analyzing-web-site-performance-with-firefox/#comments Sun, 14 Mar 2010 21:51:01 +0000 Vinay http://www.skill-guru.com/blog/?p=1725 Web developers and applications developers must have faced this problem related to performance of their Websites.

In this post I will focus of how to track website performance. Remember the websites behave different under different browsers so if your site loads faster in FireFox , it may not load with same speed in IE.

Firefox has some very good plugins to track the performance of your website. The two plugins which I really like are

1. Yslow : ySlow analyzes web pages and suggest how to improve performance based on yahoo’s rule for high performance website. You may not agree with some of the recommendations but nevertheless , it gives very good feedback.

2. FireBug : Firebug is not only an excellent  tool for editing and debugging java script, html , css  but also helps you analyze the performance of pages.

Let us analyze Skill-Guru with Yslow and see how it performs . After installing Yslow in your firefox , you will need to restart the browser.

Open the site , in our case www.skill-guru.com . On right side you will see a icon on right side of firefox bottom bar. Click on that.  You will be shown a screen as below.

Click on Run Test

YSlow Welcome

Once test is run ,  you can see the results under different tabs. Some o them would be like

Yslow performance

As you can see , we are not gzipping files and this will be pointed out by Yslow.

Yslow grades  your site based on number of parameters.

YSlow Grade

Overall Skill-guru performs reasonably well in performance although we could incorporate some suggestions of Yslow.

This YSlow user guide suggesting the best practices for designing web pages.

Once the performance of Skill-Guru is improved based on YSlow recommendations, we will post the results.

]]> http://www.skill-guru.com/blog/2010/03/14/analyzing-web-site-performance-with-firefox/feed/ 0 Open new tab instead of new window in Firefox http://www.skill-guru.com/blog/2010/03/12/open-new-tab-instead-of-new-window-in-firefox/ http://www.skill-guru.com/blog/2010/03/12/open-new-tab-instead-of-new-window-in-firefox/#comments Sat, 13 Mar 2010 02:23:04 +0000 Vinay http://www.skill-guru.com/blog/?p=1738 We had a requirement in which we wanted to open an applet in a new tab instaed of new window.

Here is how to do it

window.open(”, server[0], ‘height=1,width=1,left=1,top=1,status=yes,scrollbars=yes,resizable=yes’);

change this to

window.open(”, server[0]);

This will open the applet in new tab. As soon as you remove sizing parameters, it will open as a new tab.

But there is one issues here. The focus is on the applet tab instead on main screen.
To resolve this , change default settings in firefox config.

browser.tabs.loadDivertedInBackground=true

How to do this ?

Changing default settings in Firefox

Type about:config in firefox address bar . It will show the following screen with warning

firefxo config settings

Click on “I will be careful I promise”. Then you will see the list of properties. Look for browser.tabs.loadDivertedInBackground which is by default false.  Double click on it and the value changes.

browser.tabs.loadDivertedInBackground=true.

Also check for this property browser.link.open_newwindow.

browser.link.open_newwindow = 3

Its value should be 3.

After these changes once you run your application,  the focus comes back on main window.

Since IE 7  supports tab , this should work on IE7. In IE6 it opens in a new window (there is no tab support in IE 6)

]]> http://www.skill-guru.com/blog/2010/03/12/open-new-tab-instead-of-new-window-in-firefox/feed/ 0 Performance improvement with Firefox 3.5 http://www.skill-guru.com/blog/2009/09/22/performance-improvement-with-firefox-3-5/ http://www.skill-guru.com/blog/2009/09/22/performance-improvement-with-firefox-3-5/#comments Wed, 23 Sep 2009 01:59:20 +0000 Vinay http://www.skill-guru.com/blog/?p=659 We had an application in production running on I. You must be wondering who the hell is still on IE6.

But we have a very heavy UI with touch screen keyboard functionality and our UI consists of Yahoo’s YUI 2.7 and JSP and JSTL.  Initially we never supported Firefox and then we did not had bandwidth to fix the whole application.

The new version of application when launched had a very bad performance in field with page load times > 15 sec.

Within our facility , even on QA server we had load time of < 7 seconds on IE. The same application loaded in <4 sec on firefox.

In Firefox 3.5, Mozilla introduced a new high-performance JavaScript engine called TraceMonkey that uses just-in-time compilation and an optimization technique called tracing to deliver faster JavaScript execution.

A decision was taken to upgrade the application to support Firefox 3.5 and we updated the application.

We are scheduled to go live end of this week with new version but QA and beta testers are pretty pleased with what they are seeing in terms of performance improvement.

Will keep you posted.

]]> http://www.skill-guru.com/blog/2009/09/22/performance-improvement-with-firefox-3-5/feed/ 1 Problems with debugging with Firefox 3.5 and firebug ? http://www.skill-guru.com/blog/2009/07/06/problems-with-debugging-with-firefox-3-5-and-firebug/ http://www.skill-guru.com/blog/2009/07/06/problems-with-debugging-with-firefox-3-5-and-firebug/#comments Mon, 06 Jul 2009 21:23:28 +0000 Vinay http://www.skill-guru.com/blog/?p=100 I upgraded my browser to  new version of Firefox 3.5 and then upgraded all the add ons which I was using , particularly Firebug . I  am now using Firebug 1.4.0b4

There has been some changes in the new version of firebug as compared to old 1.3 version. You can read the changes from their blog here FireBug1.4

One of the problems I faced was activating the tabs. I had to explicitly activate the script tab and the console tab.

Second issue was debugger. My debugger was not running even though i had set the break points. When I went through the blog post  of firebug, I understood the reason.

You would have to enable the firebug by either popping it in a new window or always keeping it up. If you minimize it , it will assume that you are suspending firebug and will not get activated.

Since my buttons were at bottom of page, I had to minimize the firebug which caused the debugger to be suspended.

So I popped the firebug in new window , reloaded the page and my debugger starts to work.

Happy firebugging!!!

]]> http://www.skill-guru.com/blog/2009/07/06/problems-with-debugging-with-firefox-3-5-and-firebug/feed/ 0