This is how I see the text long area field in Standard layout in salesforce. How can I limit the visibility of it to 3 lines and to provide the option to the user to expand it. Is there any way to achieve it in Salesforce.
You have to write custom visual force page to achieve this kind of functionality. Salesforce does not support to view excrete of data or visible only some selected lines.
You can create a custom field and populate the n (number of lines) lines from long text field by creating trigger.
Field Definition Configurations #Visible Lines: The number of lines option on the field is only taken into account in edit mode only and will display all available line in detail mode.
I hope this information will help!!