CODEWITHSUNDEEP
css
Chris
Chris

Reputation: 4728

CSS transition background color without a hover

I have a div called time-box. Sometimes I will also include an additional class called countdown. If countdown is added then I would like to use a CSS transition effect so the background changes to be red over the course of 60 seconds. In other words, each second that passes the red background gets a little wider until eventually all of the green background has gone.

I have found similar posts here but they all seem to relate to hover

Here is a fiddle

https://jsfiddle.net/e2vbheew/

Upvotes: 0

Views: 840

Answers (3)

sol
sol

Reputation: 22949

Using CSS animation property...

.time-box {
  height: 27px;
  text-align: center;
  background-color: #25E57B;
  font-size: 2rem;
  padding: 0px;
  font-size: 1.2rem;
  text-transform: uppercase;
  padding: 3px 5px 3px 5px;
  font-weight: 600;
  height: auto;
  position: relative;
  z-index: 1;
}

.time-box.countdown:before {
  content: '';
  width: 0;
  height: 100%;
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  background: red;
  animation: countdown 60s forwards;
  z-index: -1;
}

@keyframes countdown {
  0% {
    width: 0;
  }
  100% {
    width: 100%;
  }
}
<div class="time-box">
  12:00
</div>

<div class="time-box countdown">
  <span>12:00</span>
</div>

Upvotes: 1

kball
kball

Reputation: 1079

I don't know a "simple" way to get what you want going from left to right, but there's a way you can create it using before and after pseudoelements. The key here is I'm going to create a :before pseudoelement that has the new background that transitions across, and an :after pseudoelement that replicates the content and puts it on top of the before, so it's still visible. This required putting the content in an attribute on the div so I could reference it in the 'content' of the pseudoelement. If you had more complex content inside, you could probably do away with the :after and simply give the internal content position and z-index to make sure it's visible. Here's the resulting CSS

.time-box {
  height: 27px;                                 
  text-align: center;
  background-color: #25E57B;    
  font-size:2rem;
  padding:0px;
  font-size:1.2rem;
  text-transform:uppercase;
  padding:3px 5px 3px 5px;;
  font-weight:600;
  height:auto;
  position: relative;
}
.time-box:before {
  background-color: red;
  position: absolute;
  left:0;
  top: 0;
  height: 100%;
  width: 0;
  content: " ";
  transition: width 60s ease;
}
.countdown:after {
  content: attr(data-content);
  width: 100%;
  text-align: center;
  height: 100%;
  position: absolute;
  left: 0;
  top: center;
  z-index: 1;
}
.countdown:before {
    width:100%;
}

And updated fiddle: https://jsfiddle.net/tunzwqd7/2/

Upvotes: 2

JDewitt
JDewitt

Reputation: 557

You would need to add a maximum and a little more math to make the 100% divisible by 60, but this should get you on the right track. Currently this code updates every second and adds 1% to the progress bar width with each iteration.

var time = 0;
var bar = document.querySelector('.countdown .progress-bar');

window.setInterval(function(){
	time++;
  bar.style.width = time+"%";
}, 1000);
.time-box {
	height: 27px;									
	text-align: center;
	background-color: #25E57B;	
	font-size:2rem;
	padding:0px;
	font-size:1.2rem;
	text-transform:uppercase;
	padding:3px 5px 3px 5px;;
	font-weight:600;
	height:auto;
  position: relative;
}

.progress-bar {
  display: none;
}

.countdown .progress-bar {
  display: block;
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  background: red;
  width: 0%;
  z-index: 1;
  transition: all 0.3s ease-out;
}

.countdown p {
  z-index: 2;
  position: relative;
}
<div class="time-box">
  <p>12:00</p>
  <div class="progress-bar"></div>
</div>

<div class="time-box countdown">
  <p>12:00</p>
  <div class="progress-bar"></div>
</div>

Upvotes: 1

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