<label><input type="checkbox" name="w3tr"> w3tr</label>
<label><input type="checkbox" name="w3tr"> w3tr</label>
jQuery.fn.extend({
  check: function() {
    return this.each(function() {
      this.checked = true;
    });
  },
  uncheck: function() {
    return this.each(function() {
      this.checked = false;
    });
  }
});
$( "input[type='checkbox']" ).check();

External CSS

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External JavaScript

  1. //cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js