Google-sheets – Multiple custom menu order

Don't use several onEdit-functions. Places place both IF-statements in the same tag.

Also, you shouldn't have semicolons after the IF-statements brackets.

function onEdit() {
 var s = SpreadsheetApp.getActiveSheet();
 if( s.getName() == "General Meeting Attendance Roster" ) { //checks that we're on the correct sheet
       s.getRange('S6').setValue("Roster last updated: " + (new Date()));
  }

 if( s.getName() == "Master Chapter Roster" ) { //checks that we're on the correct sheet
       s.getRange('K1').setValue("Chapter Roster last updated: " + (new Date()));
  }
}

With the following script you can restrict access (view only) to your Google Spreadsheet.

Code

function setUsers() {  
  var date = new Date(), day = date.getDay(), hour = date.getHours();
  var monday = 1, friday = 5;
  if((day == monday && hour == 8) || (day == friday && hour == 14)) {
    var sProp = PropertiesService.getScriptProperties();
    if(!sProp.getProperty('day')) { 
      sProp.deleteAllProperties();
      sProp.setProperty('day', day);
      var ss = SpreadsheetApp.getActiveSpreadsheet();
      switch(day) {
        case monday:
          ss.addEditors(ss.getViewers());
          break;
        case friday:
          var editors = ss.getEditors(); 
          for(var i = 0, iLen=editors.length; i < iLen; i++) {
            var user = editors[i];
            ss.removeEditor(user);
            ss.addViewer(user);
          }
          break;
      }      
    }    
  }
  return;
}

Trigger

Explained

The trigger is only fired when it's a Monday or a Friday and only on those specific times. After that it will check whether it hasn't been triggered once before, by looking up in the scripts memory. If nothing is found for that day, then delete all other entries and create a new one. This way, if the script is triggered again, it will find an entry and skip to return. The switch statement makes it possible to switch between the days and the different actions to make. On Mondays, the existing viewers need to be added as editors. This can be done via a batch operation (at once). On Fridays the editors need to be removed first in order to add them as viewers.

Notes

I've tested it against two of my own accounts and it worked. As far as I know, no messages are being send about the user being added as viewer or as an editor (which is the case when you do that manually). In the editor mode, the viewer mode is being enforced automatically. This isn't the case when the user is in the viewer mode. There the user needs to refresh the window (F5).

If you the set trigger on a 5 minutes interval, then in theory the time frame can be missed by 5 minutes. If you choose to pick the 1 minute interval, then this will be minimized to 1 minute.

Another option would be to create a trigger each and every time. This way the set time can be programmatically triggered (even thought the triggers are bound to be executed give or take 15 minutes, see reference²).

Add the code under Tools > Script editor and press the bug button to authenticate the script. Furthermore, create a trigger by selecting Resources > Current project's triggers.

Setback

There's one huge setback to this solution however. Everyone, added as an editor, will be able to see and change the code and there's no way to avoid that, see reference¹.

Reference

1. https://stackoverflow.com/q/16075446/1536038
2. https://developers.google.com/apps-script/reference/script/clock-trigger-builder