getting previous element's html in jquery-CodePudding

I have a list of divs that all have class "leftNav". When a user clicks some arrow (previous), i want to grab the previous div and mark it. Using .prev('.leftNav') or .prevAll('.leftNav') doesnt seem to work. If user is currently on 15 and clicks previous, I want the html from 14.

$('.lastProduct').click(function() {
    $('.leftNav').each(function() {
      if ($(this).hasClass('selected')) {
        var html = $(this).prevAll().html();
        //Also tried - var html = $(this).prev().html();
        //Also tried - var html = $(this).prev('.lastNav').html();
        //Also tried - var html = $(this).prevAll('.lastNav').html();
        alert(html);
      }
    })
  })
})

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class='row'>
  <div class='lastNav' id='13'>13</div>
</div>
<div class='row'>
  <div class='lastNav' id='14'>14</div>
</div>
<div class='row'>
  <div class='lastNav selected' id='15'>15</div>
</div>
<div class='row'>
  <div class='lastNav' id='16'>16</div>
</div>


<input type='button' class='lastProduct' value='Previous'>

all of those attempts result in "undefined"

What am I missing?

CodePudding user response：

Assuming the mismatch of the leftNav and lastNav classes in your code is just a typo, then you don't need an each() loop here.

You can directly select the .selected instance and traverse the DOM to find the parent .row using closest(). From there you can use prev() and find() to target the relevant .lastNav element before updating the classes on each of them.

$('.lastProduct').on('click', function() {
  const $current = $('.leftNav.selected');
  const $row = $current.closest('.row');
  const $prev = $row.prev().find('.leftNav');

  if ($prev.length) {
    $current.removeClass('selected');
    $prev.addClass('selected');
    
    const prevText = $prev.text();
    console.log(prevText);
  }
})

.selected {
  color: #C00;
  font-weight: 900;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.6.1/jquery.min.js"></script>
<div >
  <div  id="13">13</div>
</div>
<div >
  <div  id="14">14</div>
</div>
<div >
  <div  id="15">15</div>
</div>
<div >
  <div  id="16">16</div>
</div>

<button type="button" >Previous</button>