动画时弹出底部块

$('.test').click(function() {
  var test = $(this).prev();
  if (test.innerHeight() == 0) {
    test.animate({
      height: test.prop('scrollHeight') + "px",
    }, 1000);
  } else {
    test.animate({
      height: 0,
    }, 1000);
  }
});

p {
  padding: 0px;
  margin: 0px;
}

.container {
  position: relative;
  padding-top: 40px;
}

.showhide {
  position: absolute;
  left: 0px;
  top: 0px;
}

.test-block {
  background-color: #E3DEDE;
  height: 0;
  overflow: hidden;
}

.test {
  margin-top: 10px;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="container">
  <div class="showhide">
    <p class="test-block">The best products begin with the best ingredients. Flour is milled only from select grades of the best wheat grains; the best nature has to offer, it looks like white powder. We have many varieties and formats for diverse applications.High quality
      grade. This sort of flour is pretty clear from which is preparing only from well-peeled grains. This grade of flour characterize by a low content of gluten and large amount of starch. This grade of flour has white color with a light milky shade.
      This grade often use in cooking, because batch turns out splendid and porous.The first grade of flout. This is the most popular grade, which allows for a small number of grain shells. This grade of flour is characterize large amount of gluten, which
      makes it possible to get a very elastic dough. This grade of flour has a light yellow color. Batches turns out volumetric and fragrant.The second grade of flour. This grate is characterized by a darker grayish color, which has a large number of
      grain envelopes this is allowing in the composition.</p>
    <button class="test">test</button>
  </div>
  <p>
    The first grade of flout. This is the most popular grade, which allows for a small number of grain shells. This grade of flour is characterize large amount of gluten, which makes it possible to get a very elastic dough. This grade of flour has a light
    yellow color. Batches turns out volumetric and fragrant.The second grade of flour. This grate is characterized by a darker grayish color, which has a large number of grain envelopes this is allowing in the composition.
  </p>
</div>

$('.test').on('click', function() {
  $(this).closest('.showhide').find('.test-block').slideToggle(1000);
});

p {
  padding: 0px;
  margin: 0px;
}

.container {
  position: relative;
  padding-top: 40px;
}

.showhide {
  position: absolute;
  left: 0px;
  top: 0px;
}

.test-block {
  background-color: #E3DEDE;
  display: none;
}

.test {
  margin-top: 10px;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="container">
  <div class="showhide">
    <p class="test-block">The best products begin with the best ingredients. Flour is milled only from select grades of the best wheat grains; the best nature has to offer, it looks like white powder. We have many varieties and formats for diverse applications.High quality
      grade. This sort of flour is pretty clear from which is preparing only from well-peeled grains. This grade of flour characterize by a low content of gluten and large amount of starch. This grade of flour has white color with a light milky shade.
      This grade often use in cooking, because batch turns out splendid and porous.The first grade of flout. This is the most popular grade, which allows for a small number of grain shells. This grade of flour is characterize large amount of gluten, which
      makes it possible to get a very elastic dough. This grade of flour has a light yellow color. Batches turns out volumetric and fragrant.The second grade of flour. This grate is characterized by a darker grayish color, which has a large number of
      grain envelopes this is allowing in the composition.</p>
    <button class="test">test</button>
  </div>
  <p>
    The first grade of flout. This is the most popular grade, which allows for a small number of grain shells. This grade of flour is characterize large amount of gluten, which makes it possible to get a very elastic dough. This grade of flour has a light
    yellow color. Batches turns out volumetric and fragrant.The second grade of flour. This grate is characterized by a darker grayish color, which has a large number of grain envelopes this is allowing in the composition.
  </p>
</div>