JSFiddle - React, Tailwind, and code Playground

HTML

<table>
    <thead>
        <tr>
            <th><input type="checkbox" data-bind="checked: SelectAll" /> </th>
          
            <th><input type="checkbox" data-bind="checked: SelectAll2"/> </th>
            
        </tr>
    </thead>
    <tbody data-bind="foreach: $data.Countries">
        <tr>
            <td>
             
              <input type="checkbox" data-bind="checked: Selected" />   
              
            </td>
     
             <td>
              <input type="checkbox" data-bind="checked: Selected2" /> 
            </td>
          
            
        </tr>
    </tbody>
    
</table>

<button data-bind="click:selectedboth">
  click me
</button>

JavaScript

function CheckViewModel() {
    var self = this;

    self.Countries = ko.observableArray(
    							[
                    new Country("Australia"),
                  	new Country("India"),
                  	new Country("Russia"),
                    new Country("United Kingdom"),
                    new Country("United States")              
                  ]);
    
    self.SelectAll = ko.computed({
        read: function() {
            var country = ko.utils.arrayFirst(self.Countries(), function(ctr) {
                return !ctr.Selected();
            });
            return country == null;           
        },
        write: function(value) {
            ko.utils.arrayForEach(self.Countries(), function (ctr) {
                ctr.Selected(value);
            });
        }
    }).extend({ throttle: 1 });
    
    self.SelectAll2 = ko.computed({
        read: function() {
            var country = ko.utils.arrayFirst(self.Countries(), function(ctr) {
                return !ctr.Selected2();
            });
            return country == null;           
        },
        write: function(value) {
            ko.utils.arrayForEach(self.Countries(), function (ctr) {
                ctr.Selected2(value);
            });
        }
    }).extend({ throttle: 1 });
    
    var cou = new Country();
    
    self.selectedboth = function(){
    	if(cou.Selected(true) && cou.Selected2(true)) {
      	alert("you selected both please only chose one checkbox");
      }
      else if((cou.Selected(true) && cou.Selected2(false)) || (cou.Selected(false) && cou.Selected2(true)))
      {
      	alert("Succesfully Submitted");
      }
    }
    
  

}



Country = function (name) {
    this.CountyName = name;
    this.Selected = ko.observable(false);
    this.Selected2 = ko.observable(false);
}


ko.applyBindings(new CheckViewModel());