'Position: sticky' not sticking

Question

I have created a sidebar and I am simply trying to make it stick about 15px under the header when the user scrolls down. I initially was using JS for this but it really bogged my page speed down and things got choppy. I found that position sticky should work for most browsers, however my sidebar is not sticking on scroll.

I have read in various places to make sure there is no height set and overflow of any kind to the parent element, which it is not. So I am struggling to find the cause of the problem. I am wondering if there are other factors that I did not find online that could have an effect on position:sticky

.btn.sidebar {
  backface-visibility: hidden;
  box-shadow: 0 0 1px rgba(0, 0, 0, 0);
  display: inline-block;
  position: relative;
  vertical-align: middle;
  width: 100%;
  background: rgba(255, 255, 255, .6);
  border-radius: 0;
  font-size: 22px;
  transition: ease .5s;
}

.btn.sidebar:hover {
  background: #97B2AC;
  color: #fff;
}

p.contact-text {
  color: #eee;
  text-align: center;
}

div.modal-form-sidebar {
  position: sticky;
  position: -webkit-sticky;
  top: 0px;
  font: 95% Arial, Helvetica, sans-serif;
  width: 320px;
  padding: 16px;
  background: #5d84a1;
}

.modal-form-sidebar h1 {
  background: rgba(255, 255, 255, .4);
  padding: 13px 0;
  font-size: 140%;
  font-weight: 300;
  text-align: center;
  color: #fff;
  margin: 0;
}

.modal-form-sidebar input[type="text"],
.modal-form-sidebar input[type="date"],
.modal-form-sidebar input[type="datetime"],
.modal-form-sidebar input[type="email"],
.modal-form-sidebar input[type="number"],
.modal-form-sidebar input[type="search"],
.modal-form-sidebar input[type="time"],
.modal-form-sidebar input[type="url"],
.modal-form-sidebar textarea,
.modal-form-sidebar select {
  -webkit-transition: all 0.30s ease-in-out;
  -moz-transition: all 0.30s ease-in-out;
  -ms-transition: all 0.30s ease-in-out;
  -o-transition: all 0.30s ease-in-out;
  outline: none;
  box-sizing: border-box;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  width: 100%;
  background: #fff;
  margin-bottom: 4%;
  border: 1px solid #ccc;
  padding: 3%;
  color: #555;
  font: 95% Arial, Helvetica, sans-serif;
}

.modal-form-sidebar input[type="text"]:focus,
.modal-form-sidebar input[type="date"]:focus,
.modal-form-sidebar input[type="datetime"]:focus,
.modal-form-sidebar input[type="email"]:focus,
.modal-form-sidebar input[type="number"]:focus,
.modal-form-sidebar input[type="search"]:focus,
.modal-form-sidebar input[type="time"]:focus,
.modal-form-sidebar input[type="url"]:focus,
.modal-form-sidebar textarea:focus,
.modal-form-sidebar select:focus {
  box-shadow: 0 0 5px #5d84a1;
  padding: 3%;
  border: 1px solid #5d84a1;
}

.modal-form-sidebar input[type="submit"],
.modal-form-sidebar input[type="button"] {
  box-sizing: border-box;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  width: 100%;
  padding: 3%;
  background: #5d84a1;
  border-bottom: 2px solid #374F60;
  border-top-style: none;
  border-right-style: none;
  border-left-style: none;
  color: #fff;
}

.modal-form-sidebar input[type="submit"]:hover,
.modal-form-sidebar input[type="button"]:hover {
  background: #7d9cb3;
}

<div class="modal-form-sidebar">

  <p class="contact-text">Text here</p>

  <h1>Email Us</h1>
  <form action="#" id="client_capture_sidebar" method="POST" onsubmit="submitted=true;" target="hidden_iframe" role="form">

    <input type="text" name="field1" placeholder="Your Name" />
    <input type="email" name="field2" placeholder="Email Address" />
    <input type="email" name="field2" placeholder="Phone Number" />
    <textarea name="field3" placeholder="Type your Message"></textarea>
    <input type="submit" value="Send" />

  </form>
  <br>
  <div class="white-txt">or</div>
  <br>
  <h1>Call Us</h1>
  <a class="btn sidebar" href="tel:1-222-222-2222"><i class="fa fa-phone" aria-hidden="true"></i>(222) 222-2222</a>

</div>

Answer 1

I assume the reason it is not working is because there is no height to your parent container. position:sticky will only fix the element to the height of your parent container. So in your case there is no height of the parent container so once it scrolls to the sticky element there is no distance in the parent container for the sticky element to travel so it looks like nothing is happening because when the sticky element reaches the top it acts like the position goes from static to fixed until the window reaches the bottom of your parent element. So when your element becomes fixed there is a height of 0 in you parent container. I suggest you add your position:sticky to the .col-md-4 instead of the sidebar itself.

Since i don't know what your markup looks like or what version of bootstrap you are using I just assume you are using bootstrap 3 and have created a sample markup located here:

Fiddle Demo

In the demo I have added position:sticky to the col-xs-4 and it works. If you remove that and add it to the sidebar itself it will not work. Now if you scroll all the way down you will see that the sticky element will stop when it hits the red div below. This is because the height for the parent of the sticky element has ended.

So in your case since when the sticky element is removed from the div the height of your parent div is 0 and there is no room for it to scroll. I suggest doing like what I did in my demo and add position:sticky to the col-md-4 instead of the sidebar itself.

Answer 2

It does work but where position:sticky is implented. see https://caniuse.com/#search=sticky

add some content to see it sticking and if it behaves as you expect , below a snippet where it sticks untill bottom pushes it up. It is actually the correct behavior.

.btn.sidebar {
  backface-visibility: hidden;
  box-shadow: 0 0 1px rgba(0, 0, 0, 0);
  display: inline-block;
  position: relative;
  vertical-align: middle;
  width: 100%;
  background: rgba(255, 255, 255, .6);
  border-radius: 0;
  font-size: 22px;
  transition: ease .5s;
}

.btn.sidebar:hover {
  background: #97B2AC;
  color: #fff;
}

p.contact-text {
  color: #eee;
  text-align: center;
}

div.modal-form-sidebar {
  position: sticky;
  position: -webkit-sticky;
  top: 0px;
  font: 95% Arial, Helvetica, sans-serif;
  width: 320px;
  padding: 16px;
  background: #5d84a1;
}

.modal-form-sidebar h1 {
  background: rgba(255, 255, 255, .4);
  padding: 13px 0;
  font-size: 140%;
  font-weight: 300;
  text-align: center;
  color: #fff;
  margin: 0;
}

.modal-form-sidebar input[type="text"],
.modal-form-sidebar input[type="date"],
.modal-form-sidebar input[type="datetime"],
.modal-form-sidebar input[type="email"],
.modal-form-sidebar input[type="number"],
.modal-form-sidebar input[type="search"],
.modal-form-sidebar input[type="time"],
.modal-form-sidebar input[type="url"],
.modal-form-sidebar textarea,
.modal-form-sidebar select {
  -webkit-transition: all 0.30s ease-in-out;
  -moz-transition: all 0.30s ease-in-out;
  -ms-transition: all 0.30s ease-in-out;
  -o-transition: all 0.30s ease-in-out;
  outline: none;
  box-sizing: border-box;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  width: 100%;
  background: #fff;
  margin-bottom: 4%;
  border: 1px solid #ccc;
  padding: 3%;
  color: #555;
  font: 95% Arial, Helvetica, sans-serif;
}

.modal-form-sidebar input[type="text"]:focus,
.modal-form-sidebar input[type="date"]:focus,
.modal-form-sidebar input[type="datetime"]:focus,
.modal-form-sidebar input[type="email"]:focus,
.modal-form-sidebar input[type="number"]:focus,
.modal-form-sidebar input[type="search"]:focus,
.modal-form-sidebar input[type="time"]:focus,
.modal-form-sidebar input[type="url"]:focus,
.modal-form-sidebar textarea:focus,
.modal-form-sidebar select:focus {
  box-shadow: 0 0 5px #5d84a1;
  padding: 3%;
  border: 1px solid #5d84a1;
}

.modal-form-sidebar input[type="submit"],
.modal-form-sidebar input[type="button"] {
  box-sizing: border-box;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  width: 100%;
  padding: 3%;
  background: #5d84a1;
  border-bottom: 2px solid #374F60;
  border-top-style: none;
  border-right-style: none;
  border-left-style: none;
  color: #fff;
}

.modal-form-sidebar input[type="submit"]:hover,
.modal-form-sidebar input[type="button"]:hover {
  background: #7d9cb3;
}

.scrollme {overflow:hidden;height:200vh;background:pink;margin:1em;}
footer {
height:25vh;background:gray;margin:1em;}

<div class="modal-form-sidebar">

  <p class="contact-text">Text here</p>

  <h1>Email Us</h1>
  <form action="#" id="client_capture_sidebar" method="POST" onsubmit="submitted=true;" target="hidden_iframe" role="form">

    <input type="text" name="field1" placeholder="Your Name" />
    <input type="email" name="field2" placeholder="Email Address" />
    <input type="email" name="field2" placeholder="Phone Number" />
    <textarea name="field3" placeholder="Type your Message"></textarea>
    <input type="submit" value="Send" />

  </form>
  <br>
  <div class="white-txt">or</div>
  <br>
  <h1>Call Us</h1>
  <a class="btn sidebar" href="tel:1-222-222-2222"><i class="fa fa-phone" aria-hidden="true"></i>(222) 222-2222</a>

</div>
<div class="scrollme">tall div</div>
<footer>footer</footer>