using html and javascript [closed]

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when clicking on a option in drop down list another sub field must be opened using html and javascript

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$("#drop-down").change(function() {
  if ($("#drop-down").val() == "more") { /* Or whatever value you're testing for */
    $("#space-for-new-drop-down").html($("#space-for-new-drop-down").html() +
      "<input type=\"text\" size=\"5\" id=\"second-drop-down\" />"
    );
  }
});