Validation of SPO List Form fields Instantly when a Field loses focus

Dear Community,

I would like to validate SharePoint Online List Form fields instantly when a Field loses focus instead of validating at very end by clicking on SAVE button in Form and as discussed in the Website URL below. 

https://www.codeproject.com/Questions/777537/Check-and-Validate-input-field-when-loses-focus

VALIDATIONS NEEDED: A) First Letter CAPS, B) Removing Leading and Trailing spaces in Text Field.

Any MS documentation or similar solution would be great to implement same. Kindly advise

Thank You,

Arun