小编viv*_*odi的帖子

function add() {
  var new_chq_no = parseInt($('#total_chq').val()) + 1;
  var new_input = "<input type='text' id='new_" + new_chq_no + "'>";
  $('#new_chq').html(new_input);
}

function remove() {
  var last_chq_no = $('#total_chq').val();
  if (last_chq_no > 1) {
    $('#new_' + last_chq_no).append('');
    $('#total_chq').val(last_chq_no - 1);
  }
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="text">
<button onclick="add()">Add</button>
<button onclick="remove()">remove</button>
<div id="new_chq"></div>
<input type="hidden" value="1" id="total_chq">

function moreitem() {
  document.getElementById('tottr').value = parseInt(document.getElementById('tottr').value) + 1;
  ain = document.getElementById('tottr').value;
  $('#mytable tbody tr:last')
    .after("<tr><td><select name='pid[]' id='' class='form-control' onchange='getstock(this.value,'st" + ain + "','pc" + ain + "')'><option value=''>Select Product</option><option value='1'>Drink</option></select></td><td><input type='text' id='st" + ain + "'  placeholder='Available Stock' class='form-control'></td><td><input type='text' id='qty" + ain + "' onchange='gettot(this.value,ain)' name='qty[]' placeholder='Quantity' class='form-control'></td><td><input type='text' id='pc" + ain + "'  name='pprice[]' placeholder='Per Piece Price' class='form-control'></td><td><input type='text'  name='tprice[]' placeholder='Total Price' id='tp" + ain + "' class='form-control'></td></tr>");
}

function …

function chk() {
  var a = $('#chkAll').prop('checked');

  if (a == true)
    $('.hobbie').attr('checked', 'checked');
  else
    $('.hobbie').removeAttr('checked');
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
Select All <input onclick="chk()" type="checkbox" id="chkAll">
<br>
<input type="checkbox" class="hobbie">
<input type="checkbox" class="hobbie">
<input type="checkbox" class="hobbie">
<input type="checkbox" class="hobbie">