Website homepage JS animation stops on returning to it from another page

Question

I inserted a simple typewriter animation on my homepage with code from here with only minor HTML edits to personalize the content.

https://codepen.io/hi-im-si/pen/DHoup.

    <h5>
  <body>Hi! My name is Kritika. I am</body>
  <a="" class="typewrite" data-period="2000" data-type='[ "designer.", "a creative.", "a storyteller.", "an entrepreneur." ]'>
    <span class="wrap"></span>
  </a>
</h5>

<style>
  body {
  text-align: left;
  text-color:#ce3635;
  margin-top:25%;
}
</style>

<script>
  var TxtType = function(el, toRotate, period) {
        this.toRotate = toRotate;
        this.el = el;
        this.loopNum = 0;
        this.period = parseInt(period, 10) || 2000;
        this.txt = '';
        this.tick();
        this.isDeleting = false;
    };

    TxtType.prototype.tick = function() {
        var i = this.loopNum % this.toRotate.length;
        var fullTxt = this.toRotate[i];

        if (this.isDeleting) {
        this.txt = fullTxt.substring(0, this.txt.length - 1);
        } else {
        this.txt = fullTxt.substring(0, this.txt.length + 1);
        }

        this.el.innerHTML = '<span class="wrap">'+this.txt+'</span>';

        var that = this;
        var delta = 200 - Math.random() * 100;

        if (this.isDeleting) { delta /= 2; }

        if (!this.isDeleting && this.txt === fullTxt) {
        delta = this.period;
        this.isDeleting = true;
        } else if (this.isDeleting && this.txt === '') {
        this.isDeleting = false;
        this.loopNum++;
        delta = 500;
        }

        setTimeout(function() {
        that.tick();
        }, delta);
    };

    window.onload = function() {
        var elements = document.getElementsByClassName('typewrite');
        for (var i=0; i<elements.length; i++) {
            var toRotate = elements[i].getAttribute('data-type');
            var period = elements[i].getAttribute('data-period');
            if (toRotate) {
              new TxtType(elements[i], JSON.parse(toRotate), period);
            }
        }
        // INJECT CSS
        var css = document.createElement("style");
        css.type = "text/css";
        css.innerHTML = ".typewrite > .wrap { border-right: 0.08em solid #fff}";
        document.body.appendChild(css);
    };
</script>

It works in a loop when I first land on the website. But after that, if I go to another page within the website and then press the back button, home icon or home tab button to return to the homepage, the animation stops working. (Note- switching to another tab and returning to the website doesn't impact the animation at all.)

Also, I can't get the animated text to appear in the color I want it to.

I'm new to coding. Any help will be appreciated. Thanks!

score 0 · Answer 1 · answered May 26 '18 at 23:19

This is known browser behaviour. Javascript execution is slowed down in inactive tabs. Read More. You can either increase delta of setTimeout, to around 1000ms or more, or use web-workers.

Also in general, avoid doing animations with javascript, use css only.

Website homepage JS animation stops on returning to it from another page

1 Answers1