typing animated text

问题:

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?

回答1:

Just a simple approach:

$("[data-typer]").attr("data-typer", function(i, txt) {

  var $typer = $(this),
    tot = txt.length,
    pauseMax = 300,
    pauseMin = 60,
    ch = 0;

  (function typeIt() {
    if (ch > tot) return;
    $typer.text(txt.substring(0, ch++));
    setTimeout(typeIt, ~~(Math.random() * (pauseMax - pauseMin + 1) + pauseMin));
  }());

});

/* PULSATING CARET */
[data-typer]:after {
  content:"";
  display: inline-block;
  vertical-align: middle;
  width:1px;
  height:1em;
  background: #000;
          animation: caretPulsate 1s linear infinite; 
  -webkit-animation: caretPulsate 1s linear infinite; 
}
@keyframes caretPulsate {
  0%   {opacity:1;}
  50%  {opacity:1;}
  60%  {opacity:0;}
  100% {opacity:0;}
}
@-webkit-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>

<script src="//ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

So basically jQuery gets the data-text of your element, inserts character by character, and the pulsating "caret" is nothing by a CSS3 animated :after element of that SPAN.

See also: Generate random number between two numbers in JavaScript

回答2:

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.

回答3:

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);
            }
        }

    };