.prop()

use .prop() method to set checked and remove checked  for a checkbox.

// set checkbox true
$('.someCheckbox').prop('checked', true);

// remove "checked" from checkbox  using JQuery.
$('.someCheckbox').prop('checked', false);

Set checkbox checked using plain JavaScript

document.getElementById('SomeCheckBox').checked = true;

Removed checked from checkbox  using plain JavaScript

document.getElementById('SomeCheckBox').checked = true;