[RESOLVED]Performance optimization tools: JavaScript & CSS


We are using infragistics client side framework using jQuery.

JS files which are provided by infragistics are very heavy and creating lot if issues while rendering grid in IE8 version. Please see below error-

"A script on this page is causing your web browser to run slowly.
if it continues to run, your computer might become unresponsive."

Browser is not responding to render more than 100 records in IE 8 version. Based on our research we come across that js & css files which are provided by Infragistics are very heavy and need performance optimization.

Please suggest few tools which will help us to optimize infragistics js files.

You can control it by javascript following this might help you.


Hi Pravin,

Because some scripts may take an excessive amount of time to run, Internet Explorer prompts the user to decide whether to continue running the slow script. Some tests and benchmarks may use scripts that take a long time to run. Therefore, you may want to
increase the amount of time that passes before the message box appears. In Internet Explorer, the script time-out value can be changed on specific client computers by modifying a registry entry.

More details, please refer to this article:
Error message: "A script on this page is causing Internet Explorer to run slowly"

Besides, here is a similar thread, you could refer to it.

I keep getting error message to stop running script, how do I fix this?

Best Regards,

First, always try infragistics support, they’re the experts with their scripts and it’s possible that their releases have larger, heavier js for debug purposes and lighter weight ones for deployment. 

Try using bundling and minification to see if it helps performance on both css and js.

Try to use paging and/or lazy loading of data. Make sure you are only returning the data needed for the grid and not extra data. 100 records may not be a lot, but it can be if you are returning a lot of data.

Also check the F12 developer tools to look at the networking component to see if there is a slow resource that is affecting the scripts performance.

Firstly, if you are using Infragistics available Javascript components and tooling, I would highly recommend posting this issue on
their forums as they will likely be able to provide more detailed support than you might find here. Additionally, if you have an actual license for these tools, many component vendors will provide
a "premium" support service with your license that might allow you to find a solution more quickly.

Regarding performance, there are a wide variety of tools that you can use to find areas that might be causing sluggish or slower performance within your Web Applications. I usually always recommend developers to use a tool like Google’s PageSpeed Insights
or Yahoo’s YSlow service, both of which analyze various aspects of a site and find areas that can be optimized :

Consider Using a Third-Party Analyzer

I would recommend running something an analyzer like one of the following on your site :

  • Using Google PageInsights - Google’s PageInsights can help you find areas of improvement and offers suggestions on how to get your site running faster.
  • Using Yahoo’s YSlow Analyzer - Very similar to Google’s PageInsights, YSlow looks for areas that you can check to improve the performance of your site.

It will provide you with any major concerns that might be slowing down performance on your site and how to resolve these issues. You might see something like the following after running it, which will let you know what images you need to consider optimizing
and the amount of size that you will save :

A Few Additional Recommendations

A few more generic recommendations or things to check would be :

  • Ensure that you are using minified versions of your Javascript files (especially larger ones that you might be using for the Infragistics components).
  • Ensure that you are properly paging data within your Grids and if you aren’t, consider pulling smaller data-sets to see if that makes any noticeable differences.
  • Try using the Developer Tools (F12) within your browser and check the Console area to see if there are any errors that are present. These may reveal some issues that could be slowing things down.

One Final Recommendation

If you want an excellent resource that encompasses a variety of methods to improve your website or web application, I cannot recommend the Web Developer Checklist enough. There
is also an ASP.NET-specific version available on the site as well
 and one that focuses specifically on ASP.NET Performance. It’s probably one of the best single resources that I have found for
improving nearly all aspects of a website or web application.


Thanks everyone for your valuable inputs. We have already raised this issue with Infragistics support team somehow this is known issue over IE8 and they have asked us to use following patch from Microsoft


Running any patch over clients machine is NOT feasible solution. Our code works fine over IE11 where we could able to see 2,000+ records somehow IE8 is not supporting. 

I will look into the suggestions you guys have provided and see how it works. Thank you again for your valuable suggestions.

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