Can I extract specific text from the middle of a string?

It isn't worth the trouble trying to put JavaScript into your formulas as you will have a difficult time debugging your formulas and adding a lot of character escaping which makes the formulas unreadable. It is best to get out of the formula language as quickly as possible and pass the least amount of field values to the script. When you try to do parsing like this exclusively in the formula language you have to limit yourself to some upper bound of instances you can parse because the formula language has no looping or iterative methods and this process makes for jumbo formulas. In script you have no such limitations or nuisances.

Anyways I have a demo in preparation for a similar question which I should finish shortly. I will reread your question and reply further when I get a chance.

Hi,

Thanks Dan. Understood about the script in formulas - it does seem rather cumbersome. If I wanted to look into getting out of formulas though, where woudl you input the script? 

I work with imported sheets, so I'm attempting to pull the middle strings out from these imported fields. Is there a specific type of field and format I should use to make use of script?

>where woudl you input the script? 

Read these:

How Do I Setup the Image Onload Technique (IOL)?
https://community.quickbase.com/quickbase/topics/how-do-i-setup-the-image-onload-technique-iol

Pastie Database Record #294
https://haversineconsulting.quickbase.com/db/bgcwm2m4g?a=dr&rid=294

What is the Simplest IOL Example?
https://community.quickbase.com/quickbase/topics/what-is-the-simplest-iol-example

Thanks Dan - very helpful. I now have the IOL working with the alert popping up on my forms.

It looks like in order to make the .js target a specific field, I'd need to specify the field ID I'm trying to target, correct? I'm going off the example you provided here: https://community.quickbase.com/quickbase/topics/what-is-the-simplest-iol-example

So to get the middle string using this method, I'd do something like: 
$("#_fid_[field ID of field]").substring(1,4);

This code by itself doesn't seem to work though. 

I assume that I would need a separate module.js page and new IOL field for each custom js I'd like to include in the form, correct? For example, having one formula that finds a middle string and another that throws an alert would require two .js pages and two IOL fields on the form.