[рони]

[HTML run]<form>
	<input type = "text">
	<span id = "NewFields"></span>
	<br> <input name = "MyField" type = "button" value = "+" onclick = 'CreateFormElement()'>
     <input name = "MyField" type = "button" value = "-" onclick = 'CreateFormElement(true)'>
</form>
<script>
   function CreateFormElement(remove){
  var MyForm = document.getElementById('NewFields');
  var input = remove ? MyForm.querySelector(':nth-last-child(1)') : document.createElement('input');
  var br = remove ? MyForm.querySelector(':nth-last-child(2)') : document.createElement('br');

    var ap = remove ? "removeChild" : "appendChild"
 if(br)MyForm[ap](br);
  if (input){input.type = 'text';
  input.name = 'MyField';MyForm[ap](input);
}
}
</script>[/HTML]

<form>
	<input type = "text">
	<span id = "NewFields"></span>
	<br> <input name = "MyField" type = "button" value = "+" onclick = 'CreateFormElement()'>
     <input name = "MyField" type = "button" value = "-" onclick = 'CreateFormElement(true)'>
</form>
<script>
   function CreateFormElement(remove){
  var MyForm = document.getElementById('NewFields');
  var input = remove ? MyForm.querySelector(':nth-last-child(1)') : document.createElement('input');
  var br = remove ? MyForm.querySelector(':nth-last-child(2)') : document.createElement('br');

    var ap = remove ? "removeChild" : "appendChild"
 if(br)MyForm[ap](br);
  if (input){input.type = 'text';
  input.name = 'MyField';MyForm[ap](input);
}
}
</script>