javascript - Check if a HTML element exists before append -

i need way check if dynamically created hidden input element exists in document before appending it.

i know there similar questions, questions differs them because other questions seem basic appending of elements selectors e.g.

if ($('#button').length) 

checks if element #button id exists.

however in code, dynamically creating input elements, name value attributes different. need if whole element exists 1 one in loop before append it. there way in jquery?

$('input[type=radio]:checked').each(function(){  //something if($('<input type="hidden" name="data[' + $(this).val() + ']" value="' + $(this).val() + '" />').length)  {  $('#addcharacters').append('<input type="hidden" name="data[' + $(this).val() + ']" value="' + $(this).val() + '" />');  } }); 

with jquery, can use .is() function test whether element/sequence of elements match conditions specify. helpful don't have worry escaping strings. instance:

$('input:radio:checked').each(function(){     var cur = $(this).val();     if(!$('#addcharacters input:hidden')         .is(function(i,e){ return e.value==cur && e.name=='data['+cur+']'; }))     {         // append new element     } }); 

if have lot of radio elements check, you'll want move anonymous function somewhere else it's not created each radio element you're checking.

see expansive example in mini-guessing game here: https://jsfiddle.net/bv6abj7l/2/