13

I have DIV tag with text inside. Is it possible to change the text content in a loop with a typing effect, where it types out, then goes backward deleting the letters and starting all over with a new text? Is this possible with jquery?

Erik
  • 5,701
  • 27
  • 70
  • 119

3 Answers3

38

A simple approach:

const elsTyper = document.querySelectorAll("[data-typer]");
const rand = (min, max) => Math.floor(Math.random() * (max - min + 1) + min);

const typer = (el) => {
  const text = el.dataset.typer;
  const tot = text.length;
  let ch = 0;

  (function typeIt() {
    if (ch > tot) return;
    el.textContent = text.substring(0, ch++);
    setTimeout(typeIt, rand(60, 300));
  }());
};

elsTyper.forEach(typer);
/* PULSATING CARET */
[data-typer]:after {
  content:"";
  display: inline-block;
  vertical-align: middle;
  width:1px;
  height:1em;
  background: #000;
  animation: caretPulsate 1s linear infinite; 
}
@keyframes caretPulsate {
  0%   {opacity:1;}
  50%  {opacity:1;}
  60%  {opacity:0;}
  100% {opacity:0;}
}
<span data-typer="Hi! My name is Al. I will guide you trough the Setup process."></span>
<h3 data-typer="This is another typing animated text"></h3>

So basically get the data-typer string of your element, insert character by character using a random min-max timeout. The pulsating "caret" is nothing by a CSS3 animated :after pseudo element of that same SPAN.

See also: Generate random number between two numbers in JavaScript

Roko C. Buljan
  • 196,159
  • 39
  • 305
  • 313
  • Some people called *delay* – Alexander Feb 21 '13 at 23:24
  • 1
    @Alexander ...we are people? ;) haha kidding, I borrowed the term from audio engineering – Roko C. Buljan Feb 21 '13 at 23:24
  • This would be much more performant if `$('.writer')` was cached to a variable first. `var $writer = $('.writer');` – chrisM Apr 29 '14 at 14:43
  • Where does come from the formula `(Math.random()*(300-60+1)+60)` ? – Olivier Boissé Jun 13 '17 at 14:25
  • @oliv37 Simple math. That formula creates rand in min-max range. `Math.random` gives a decimal between 0..1(exclusive). Say we need random int. between 10 and 30, `(rand * 20) + 10` so the first 20 is nothing but `(max-min)` or `(30-10)`. Random (rand * 20) will logically return decimal numbers in the range 0-19.999.... Since we want 20 to be inclusive we do a `+1` like (max-min+1) now we have the range `0 - 20.999..`. Than rise the result by `10` to get ranges `10 - 30.999..`. Than use `Math.floor` or `~~` to floor the result to get **integers** in the perfect `10 - 30` range. – Roko C. Buljan Jun 13 '17 at 16:35
0

Jquery's text() method lets you set the text of an element.

http://api.jquery.com/text/

You would be able to use this to animate the contents by calling this in a loop, giving it the contents that you'd like to see in each frame.

var frames = ['t_', 'ty_', 'typ_', 'type_']

// loop over frames ... inner part reads frame and prints it
// use setInterval, etc.
$('#my-div').text( frames[i] );

I've done more complicated things by splitting the text elements and manipulating the characters but I think in your case it would be overkill.

dnewcome
  • 2,045
  • 17
  • 15
0

Typing Effect + Erasing Effect + Blinking Cursor

I modified Simon Shahriveri codepan to further add the blinking effect of the cursor. It's compatible with IE also.
Here's the end result: https://codepen.io/jerrygoyal/pen/vRPpGO

HTML:

<h1>
  <a href="" class="typewrite" data-period="2000" data-type='[ "Hi, I am Jerry.", "I am Creative.", "I Love Design.", "I Love to Develop." ]'>
    <span class="wrap"></span>
  </a>
</h1>

CSS:

body {
  background-color:#ce6670;
  text-align: center;
  color:#fff;
  padding-top:10em;
}

* { color:#fff; text-decoration: none;}

.wrap{
   animation: caret 1s steps(1) infinite;
   border-right: 0.08em solid #fff;
  padding-right: 1px;
}
@keyframes caret {
  50% {
    border-color: transparent;
  }
}

JS:

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);
            }
        }
  
    };

Another way by using just functions instead of js prototypes: https://codepen.io/jerrygoyal/pen/vRPpGO

GorvGoyl
  • 42,508
  • 29
  • 229
  • 225