# HELP - online experiment issue

**URL:** <https://discourse.psychopy.org/t/help-online-experiment-issue/45210>\
**Category:** Online experiments\
**Tags:** pavlovia\
**Created:** [July 15, 2025, 4:02pm UTC](https://discourse.psychopy.org/t/help-online-experiment-issue/45210 "2025-07-15T16:02:39Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![lolo\_bean](https://avatars.discourse-cdn.com/v4/letter/l/8baadc/32.png) [@lolo\_bean](https://discourse.psychopy.org/u/lolo_bean)\
**Post date:** [July 15, 2025, 4:02pm UTC](https://discourse.psychopy.org/t/help-online-experiment-issue/45210/1 "2025-07-15T16:02:39Z")

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When Pavlovia converted my project into an online format, it had to convert Python into Javascript. When it did, it made an ungodly amount of syntax errors. Unfortunately, deleting all the documents and re-creating the project doesn’t fix it. I’ve found that converting from the builder to Pavlovia works, or it doesn’t, and I don’t understand why. For example, throughout my JavaScript file, it just didn’t define variables before storing things in them (which is fine for Python but not JavaScript) and missing semicolons. The only thing I can think of that may have saved this from happening would have been if I’d converted my python script to java (for my code components), but the issues seem to be related to all of the builders in built components that I don’t have any control over.

Any suggestions on what could be going wrong? Any help would be appreciated.

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**Author:** ![wakecarter](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.psychopy.org/wakecarter/32/5753_2.png) [@wakecarter](https://discourse.psychopy.org/u/wakecarter)\
**Post date:** [July 15, 2025, 5:19pm UTC](https://discourse.psychopy.org/t/help-online-experiment-issue/45210/2 "2025-07-15T17:19:49Z")

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Hi,

You haven’t given much information about your experiment, or your version of PsychoPy but here are some of my relevant tips.

> [@Wakefield's Daily Tips](https://discourse.psychopy.org/t/wakefields-daily-tips/43371/19):
>
> Builder isn’t Coder I strongly discourage the use of PsychoPy Coder for the creation of psychology experiments because Builder is easier to debug, share with others and translate into PsychoJS for use online. If you already have an experiment written in Coder, pasting the code into Builder code components is not sufficient to turn it into a Builder experiment. The logic of how to arrange an experiment is slightly different because of the way Builder works with components, routines and loops. F…

> [@Wakefield's Daily Tips](https://discourse.psychopy.org/t/wakefields-daily-tips/43371/6):
>
> Use Auto → JS code components wherever possible Even if you aren’t planning to run your experiment online, using an Auto code component will help you spot syntax errors in your Python code. There are some cases where valid Python code comes up as a Syntax error on the JavaScript side but these are rare and, when you encounter then, you can switch to a Both code component and edit or delete the JavaScript side to highlight the fact that they contain code that won’t run online unedited. …

> [@Wakefield's Daily Tips](https://discourse.psychopy.org/t/wakefields-daily-tips/43371/41):
>
> ReferenceError: varName is not defined This is one of the most common errors in online experiments It is also one of the easiest to solve. The issue is one of “scope”. To define a variable so it has scope across your whole experiment, all you have to do is assign it a value. Don’t edit your JavaScript to add “var” or “let” commands. To give your variable scope assign the value in a Begin Experiment code component tab outside any clauses (i.e. no Python indents). I usually s…

> [@Wakefield's Daily Tips](https://discourse.psychopy.org/t/wakefields-daily-tips/43371/17):
>
> The answer is (almost) never to edit the generated code When you create an experiment in Builder, PsychoPy then generates a Python file which you can use to run the experiment locally and two JavaScript files suitable for running the experiment online (using current and older browsers). If something doesn’t work, there may be a temptation to make edits directly to the Python/JavaScript files rather than the Builder file. However, this is generally a bad idea for two reasons: The process is o…

> [@Wakefield's Daily Tips](https://discourse.psychopy.org/t/wakefields-daily-tips/43371/5):
>
> Developer Tools If you encounter an error in an online study, open the Developer tools console using Ctl-Shift-I in Windows/Chrome, Cmd-Opt-J or Cmd-Opt-I in Mac/Chrome, F12 in IE/Edge, Ctrl-Shift-J in Windows/Safari or Ctrl-Opt-J in Mac/Safari. Select the Console tab at the top and errors item on the left to view errors. Ignore the 404 error related to favicon.ico Look for the error that appears on the main screen and click on the link next to Scheduler.\_currentTask. Take…

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<div class="post-metadata">

**Author:** ![lolo\_bean](https://avatars.discourse-cdn.com/v4/letter/l/8baadc/32.png) [@lolo\_bean](https://discourse.psychopy.org/u/lolo_bean)\
**Post date:** [July 16, 2025, 4:37am UTC](https://discourse.psychopy.org/t/help-online-experiment-issue/45210/3 "2025-07-16T04:37:37Z")

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Thank you! I am using psychopy(v2025.1). I have gone back and fixed all the issues but now every time I try to sync to pavlovia I get this error: Traceback (most recent call last):  
File “/Applications/PsychoPy.app/Contents/Resources/lib/python3.10/psychopy/app/builder/builder.py”, line 1621, in onPavloviaSync  
File “/Applications/PsychoPy.app/Contents/Resources/lib/python3.10/psychopy/app/pavlovia\_ui/project.py”, line 854, in syncProject  
File “/Applications/PsychoPy.app/Contents/Resources/lib/python3.10/psychopy/projects/pavlovia.py”, line 916, in sync  
File “/Applications/PsychoPy.app/Contents/Resources/lib/python3.10/psychopy/projects/pavlovia.py”, line 1155, in firstPush  
File “/Applications/PsychoPy.app/Contents/Resources/lib/python3.10/psychopy/projects/pavlovia.py”, line 1321, in commit  
File “/Applications/PsychoPy.app/Contents/Resources/lib/python3.10/git/cmd.py”, line 986, in   
File “/Applications/PsychoPy.app/Contents/Resources/lib/python3.10/git/cmd.py”, line 1599, in \_call\_process  
File “/Applications/PsychoPy.app/Contents/Resources/lib/python3.10/git/cmd.py”, line 1389, in execute  
git.exc.GitCommandError: Cmd(‘/Applications/PsychoPy.app/Contents/Resources/git-core/git’) failed due to: exit code(1)  
cmdline: /Applications/PsychoPy.app/Contents/Resources/git-core/git commit -m Push initial project files  
stdout: ‘On branch master  
nothing to commit, working tree clean’

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<div class="post-metadata">

**Author:** ![wakecarter](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.psychopy.org/wakecarter/32/5753_2.png) [@wakecarter](https://discourse.psychopy.org/u/wakecarter)\
**Post date:** [July 16, 2025, 7:51am UTC](https://discourse.psychopy.org/t/help-online-experiment-issue/45210/4 "2025-07-16T07:51:14Z")

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Does your experiment contain very large files (e.g. long videos)?

Is your psyexp file in a folder which has non-experiment sub-folders (e.g. desktop, downloads, documents)?

> [@HTTP 500 error on initial git push](https://discourse.psychopy.org/t/http-500-error-on-initial-git-push/41100):
>
> OS (e.g. Win10): macOS 14.6.1 PsychoPy version (e.g. 1.84.x): 2024.2.1 Standard Standalone? (y/n) If not then what?: y What are you trying to achieve?: I’m trying to do an initial push of my project to Pavlovia - it’s a copy of an existing project but I regenerated the .js file and removed the hidden .git folder to upload it as a new project. What did you try to make it work?: I tried both clicking the sync button to create the project and clicked the “create new project” button. In both …