Disable Weekends on HTML 5 input type date

Just check the day. If it's a weekend you can reset the value and tell the user to pick something else.

const picker = document.getElementById('date1');

picker.addEventListener('input', function(e){
  var day = new Date(this.value).getUTCDay();
  if([6,0].includes(day)){
    e.preventDefault();
    this.value = '';
    alert('Weekends not allowed');
  }
});

<input id="date1" size="60" type="date" format="MM/DD/YYYY" placeholder="MM/DD/YYYY" />