LimeSurvey version:   LimeSurvey Community Edition
Version 5.3.4+220309
Own server or LimeSurvey hosting: Own server
Survey theme/template: Vanilla Theme
==================
Has anyone experienced a laggy survey on tablets? We have quite a long survey (a little over 50 questions) that does well on PCs but when users try to take it on their tablets it lags quite severely. We've tested the survey on different samsung tablets from model 5 - 8 and ASUS tablets as well and all of them lag. We have also tested on a chromebook and that gave us a similar experience. Was wondering if anyone else noticed this behavior and if there might be any solutions.

Thanks for you time!

- Tori

I assume you are not using Offlinesurveys.com, but rather open the link online in a normal mobile browser? Which is the browser that has been used?

I have run a study on smartphones recently and could not feel such a problem. We didn't have 50 questions, but as long as they are not all displayed on one page, I don't see why the amount of questions would have an impact.

I think, much more relevant would be if there are a lot of equations / calculations made during the survey, etc.

Yes, it is a link that opens in a normal mobile browser. I am told the users are using google chrome. We do have all the questions on one page so that users can just scroll. We also have about 3 questions that does calculations. Perhaps that is the issue. I will try breaking up the questions to different pages. 

I was going to try to upload a video of the lagging users are experiencing but the file is too large. I've gone ahead and created a link if you're interested in seeing the performance.
[url] iportal.ebsr.org/filr/public-link/file-d...454005580442/lag.mp4 [/url]

Well, in the video, the page seems to scroll fine. I assume you are referring to the lag between typing and showing up in the field. Not sure if this is something that has to do with Limesurvey though. Not sure if this can be solved by splitting things up into several pages.

And having everything on one page is never recommendable. If something happens, everything is lost, as everything is on one page. If you split it up, at least everything that has been sent when clicking "next" is saved in the database.

Let's see if others like Tpartner or Denis know, where the lack between typing and showing up in the survey could come from.

Yes, the scrolling is fine. It's the lag between typing and showing up in the field. I just tried the survey on my own smartphone and don't see this typing lag either. Perhaps it has something to do with tablets? Not 100% sure. I had made it as one long scrolling survey in case we decided to move this survey to the app.

torilee93 wrote:

 It's the lag between typing and showing up in the field. I just tried the survey on my own smartphone and don't see this typing lag either. Perhaps it has something to do with tablets?
 

This can happen quite often. LimeSurvey is using JavaScript to check filter, fields and inputs. Depending on the browser (speed to execute JavaScript) and the CPU of the mobile device you see a lag. Smartphones are often using better hardware that tablets (market for tablets is shrinking since years).
There is a lot of room for code improvement in LimeSurvey.Depending on your survey structure a lot of code is executed before showing the final page.

Thanks for the input everyone. Other than offline surveys, is there another method to use limesurvey when users are trying to fill out surveys in areas with little to no internet connection?

- Tori

This wouldn't change with an offline mode since the JavaScript would still run in the browser. The question is if there certain questions/questions-groups where the lagging is dominant. There you might can optimize the survey and check if there is a bug in LimeSurvey. I recommend to have two LimeSurvey installations to check with different versions. A typical lag-monster is a ranking question with filtering of answer items.

Next step would be to create a simple survey for testing with just the minimum of questions to reproduce the lag. Try different mobile browsers on that survey and attach an LSS export here.

And of course it might have nothing to do with Limesurvey at all but be a general problem between typing and the input within the browser.

So it is a good idea to test different scenarios, like Jelo suggested to determine if it is just a problem with this specific survey, a general problem with Limesurvey, a general problem with the tablets, browser, etc.