Circular countdown JavaScript from 10 to Zero

user_2398069 0
Viewed 1234

I have been trying to reverse the countdown in this demo from 10 down to zero Without luck.

I have tried reversing the countdown by doing this: 

(1*(initialOffset/time))-initialOffset )

It did reverse the animated circle but not the countdown.

Any ideas?

Thanks 

var time = 10;
var initialOffset = '440';
var i = 1

/* Need initial run as interval hasn't yet occured... */
$('.circle_animation').css('stroke-dashoffset', initialOffset-(1*(initialOffset/time)));

var interval = setInterval(function() {
    $('h2').text(i);
    if (i == time) {   
        clearInterval(interval);
        return;
    }
    $('.circle_animation').css('stroke-dashoffset', initialOffset-((i+1)*(initialOffset/time)));
    i++;  
}, 1000);
.item {
    position: relative;
    float: left;
}

.item h2 {
    text-align:center;
    position: absolute;
    line-height: 125px;
    width: 100%;
}

svg {
    transform: rotate(-90deg);
}

.circle_animation {
    stroke-dasharray: 440; /* this value is the pixel circumference of the circle */
    stroke-dashoffset: 440;
    transition: all 1s linear;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="item">
    <h2>0</h2>
    <svg width="160" height="160" xmlns="http://www.w3.org/2000/svg">
        <circle id="circle" class="circle_animation" r="69.85699" cy="81" cx="81" stroke-width="8" stroke="#6fdb6f" fill="none"/>
    </svg>
</div>

Here is also a codepen copy:

https://codepen.io/kaolay/pen/LRVxKd

javascript
4 Answers

If you update this line $('h2').text(time - i); then you'll get the numeric countdown. I also initalize i = 0 so that the starting number is 10:

var time = 10;
var initialOffset = '440';
var i = 0

/* Need initial run as interval hasn't yet occured... */
$('.circle_animation').css('stroke-dashoffset', initialOffset-(1*(initialOffset/time)));

var interval = setInterval(function() {
  $('h2').text(time - i);
  if (i == time) {   
      clearInterval(interval);
   return;
    }
    $('.circle_animation').css('stroke-dashoffset', initialOffset-((i+1)*(initialOffset/time)));
    i++;  
}, 1000);
.item {
    position: relative;
    float: left;
}

.item h2 {
    text-align:center;
    position: absolute;
    line-height: 125px;
    width: 100%;
}

svg {
    transform: rotate(-90deg);
}

.circle_animation {
  stroke-dasharray: 440; /* this value is the pixel circumference of the circle */
  stroke-dashoffset: 440;
  transition: all 1s linear;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="item">
    <h2>0</h2>
    <svg width="160" height="160" xmlns="http://www.w3.org/2000/svg">
      <circle id="circle" class="circle_animation" r="69.85699" cy="81" cx="81" stroke-width="8" stroke="#6fdb6f" fill="none"/>
    </svg>
</div>

user_85267050

Try $('h2').text(time - i); instead of $('h2').text(i);

I also added $('h2').text(time); as the 4th line to draw 10 at the beginning

Also, the first part of the circle is not animated in your code, so I changed this line:

$('.circle_animation').css('stroke-dashoffset', initialOffset-(1*(initialOffset/time)));

To this block: 

$('.circle_animation').css('stroke-dashoffset', initialOffset);
setTimeout(() => {
    $('.circle_animation').css('stroke-dashoffset', initialOffset-(1*(initialOffset/time)));
})


var time = 10;
var initialOffset = '440';
var i = 1;
$('h2').text(time); // adding 10 at the beginning if needed

/* Need initial run as interval hasn't yet occured... */
$('.circle_animation').css('stroke-dashoffset', initialOffset);
setTimeout(() => {
    $('.circle_animation').css('stroke-dashoffset', initialOffset-(1*(initialOffset/time)));
})


var interval = setInterval(function() {
    $('h2').text(time - i); // here is the clue
    if (i == time) {   
        clearInterval(interval);
        return;
    }
    $('.circle_animation').css('stroke-dashoffset', initialOffset-((i+1)*(initialOffset/time)));
    i++;  
}, 1000);
.item {
    position: relative;
    float: left;
}

.item h2 {
    text-align:center;
    position: absolute;
    line-height: 125px;
    width: 100%;
}

svg {
    transform: rotate(-90deg);
}

.circle_animation {
    stroke-dasharray: 440; /* this value is the pixel circumference of the circle */
    stroke-dashoffset: 440;
    transition: all 1s linear;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="item">
    <h2>0</h2>
    <svg width="160" height="160" xmlns="http://www.w3.org/2000/svg">
        <circle id="circle" class="circle_animation" r="69.85699" cy="81" cx="81" stroke-width="8" stroke="#6fdb6f" fill="none"/>
    </svg>
</div>

user_81315790

What exactly are you asking here? "It did reverse the animated circle but not the countdown."

you are just trying to countdown?

why not set i = 10 and then do i--

user_38427460

If you want to invert the animation just invert all states of initial values and change i to (time-i). So it goes like this:

<div class="item">
    <h2>10</h2>
    <svg width="160" height="160" xmlns="http://www.w3.org/2000/svg">
      <circle id="circle" class="circle_animation" r="69.85699" cy="81" cx="81" stroke-width="8" stroke="#6fdb6f" fill="none"/>
    </svg>
</div>

.item {
    position: relative;
    float: left;
}

.item h2 {
    text-align:center;
    position: absolute;
    line-height: 125px;
    width: 100%;
}

svg {
    transform: rotate(-90deg);
}

.circle_animation {
  stroke-dasharray: 440; /* this value is the pixel circumference of the circle */
  stroke-dashoffset: 0;
  transition: all 1s linear;
}

var time = 10;
var initialOffset = 440;
var i = 0

/* Need initial run as interval hasn't yet occured... */
$('.circle_animation').css('stroke-dashoffset', 0);

var interval = setInterval(function() {
        $('h2').text(time-i);
        if (i == time) {    
      clearInterval(interval);
            return;
    }
    $('.circle_animation').css('stroke-dashoffset', initialOffset*i/time);
    i++;  

}, 1000);

Code pen: https://codepen.io/anon/pen/Xybpge

user_73556870
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