Your best bet for this is to make good use of the built-in security that FileMaker offers.
Let's say these users should have the right to access all information but edit none of it. Assign those users the [Read Only Access] privilege set. They'll be able to click into any field, but won't be able to modify any of it.
That will probably be too restrictive. Most users will probably need to be able to edit fields in some tables but not in others. Maybe users should be able to see a layout, but not edit anything on THAT layout. The BEST way is to use privilege sets based on the user's role.
For this...Here's an example.
You have a bunch of STUDENT users who need to see the layout called IMPORTANTLAYOUT, and you don't want any of them to be able to edit any data on IMPORTANTLAYOUT. You set up a privilege set called STUDENT. You click the "Layouts:" pull down and select "Custom Privileges...". You locate IMPORTANTLAYOUT in the list, and you click "View only" so they can't modify the layout, and "View Only" for the records. They'll be able to click into all of the fields, but FileMaker will take care of letting them know they can't edit anything.
You can set access privileges for every script, every layout, every table, and every field in your database. Each privilege set can have different privileges. Nothing has to be hard-coded, you can modify the privileges for an entire group of people quickly and easily, and your database will be much more secure than if you try to create something on your own.