# How to preview latex formulas?

• Bug
Heidi
Hi Pfs,
I do not succeed to preview the latex formulas that i type in this forum.
I tried with formulas between: $$\epsilon_j$$ or between sharp characters and then i click on the preview icon.
I see that something has changed: i can more modify my text. but i do not see the result
if i click one more time then i can modify my formulas.
Was something wrong? If i post my thread , i see the resultins formulas with latex but without previewing.
edit
thanks

Mentor
Interesting. For me the "Preview" button works fine. If I click it once it goes to preview mode and shows the post with the LaTeX correctly rendered, and if I click it again then it goes back to edit mode with the LaTeX code.

@Greg Bernhardt any ideas what may prevent the Preview button from working?

jedishrfu
Homework Helper
Gold Member
I do not succeed to preview the latex formulas that i type in this forum.
In a newly-opened tab, the preview often doesn't work. Reloading the tab and clicking preview again cures that (in my Firefox browser). Once the preview works in a tab, it keeps working.

UPDATE: @Wrichik Basu has posted some cautions and a safer procedure here.

Last edited:
mfb, hmmm27, jedishrfu and 2 others
Mentor
In a newly-opened tab, the preview often doesn't work. Reloading the tab and clicking preview again cures that (in my Firefox browser). Once the preview works in a tab, it keeps working.
I was able to replicate this behavior too. Must be some sort of lazy loading where the LaTeX rendering component only loads if the page contains LaTeX on loading.

jedishrfu and FactChecker
Mentor
2022 Award
In a newly-opened tab, the preview often doesn't work. Reloading the tab and clicking preview again cures that (in my Firefox browser). Once the preview works in a tab, it keeps working.
Same in Chrome.

Another possible explanation is an unintentional double click, a problem I currently have with my mouse.

jedishrfu, Dale and FactChecker
Mentor
I've seen on some browsers where the tools when posting are all red and don't respond. I figured it had something to do with browser security ie disabling javascript support or some javascript incompatibility. I switch to another browser when that happens.

Gold Member
2022 Award
I was able to replicate this behavior too. Must be some sort of lazy loading where the LaTeX rendering component only loads if the page contains LaTeX on loading.
As per the current configuration, a page that does not have any ##\LaTeX## does not load the MathJax resources. See this post of mine in a thread on the exact same issue: https://www.physicsforums.com/threa...oes-it-work-for-you-here.1006363/post-6531460

There's a bug that you need to be careful of before refreshing the page; otherwise the entire LaTeX will get rendered in the edit box itself, and clicking on Preview will result in gibberish, and you will likely lose what you have written. See the above link for a possible workaround.

jedishrfu, Heidi, mfb and 2 others
Heidi
Thanks you Wrichik Basu.
It works now.

Wrichik Basu
OCR
I've seen on some browsers where the tools when posting are all red and don't respond.

That can happen if you click the "Toggle BB code" button. . .

That might not be what you mean, though ?

Last edited:
Wrichik Basu