使用 jQuery 实现打字机效果

编辑：我并没有真正问我原来问题中应该问的所有问题。为了帮助寻找类似答案的人更容易找到答案，问题最终是这样的：

如何制作带有闪烁光标的打字机效果，该光标在语句末尾暂停、擦除语句并写入新语句？

看看下面 Yoshi 的回答。它正是这样做的...

demo: http://jsbin.com/araget/5/ http://jsbin.com/araget/5/

/*** Plugin ***/

(function($) {
  // writes the string
  //
  // @param jQuery $target
  // @param String str
  // @param Numeric cursor
  // @param Numeric delay
  // @param Function cb
  // @return void
  function typeString($target, str, cursor, delay, cb) {
    $target.html(function(_, html) {
      return html + str[cursor];
    });

    if (cursor < str.length - 1) {
      setTimeout(function() {
        typeString($target, str, cursor + 1, delay, cb);
      }, delay);
    } else {
      cb();
    }
  }

  // clears the string
  //
  // @param jQuery $target
  // @param Numeric delay
  // @param Function cb
  // @return void
  function deleteString($target, delay, cb) {
    var length;

    $target.html(function(_, html) {
      length = html.length;
      return html.substr(0, length - 1);
    });

    if (length > 1) {
      setTimeout(function() {
        deleteString($target, delay, cb);
      }, delay);
    } else {
      cb();
    }
  }

  // jQuery hook
  $.fn.extend({
    teletype: function(opts) {
      var settings = $.extend({}, $.teletype.defaults, opts);

      return $(this).each(function() {
        (function loop($tar, idx) {
          // type
          typeString($tar, settings.text[idx], 0, settings.delay, function() {
            // delete
            setTimeout(function() {
              deleteString($tar, settings.delay, function() {
                loop($tar, (idx + 1) % settings.text.length);
              });
            }, settings.pause);
          });

        }($(this), 0));
      });
    }
  });

  // plugin defaults  
  $.extend({
    teletype: {
      defaults: {
        delay: 100,
        pause: 5000,
        text: []
      }
    }
  });
}(jQuery));


/*** init ***/

$('#target').teletype({
  text: [
    'Lorem ipsum dolor sit amet, consetetur sadipscing elitr,',
    'sed diam nonumy eirmod tempor invidunt ut labore et dolore',
    'magna aliquyam erat, sed diam voluptua. At vero eos et',
    'accusam et justo duo dolores et ea rebum. Stet clita kasd',
    'gubergren, no sea takimata sanctus est Lorem ipsum dolor sit',
    'amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr,',
    'sed diam nonumy eirmod tempor invidunt ut labore et dolore',
    'magna aliquyam erat, sed diam voluptua. At vero eos et accusam',
    'et justo duo dolores et ea rebum. Stet clita kasd gubergren,',
    'no sea takimata sanctus est Lorem ipsum dolor sit amet.'
  ]
});

$('#cursor').teletype({
  text: ['_', ' '],
  delay: 0,
  pause: 500
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<span id="target"></span>
<span id="cursor"></span>
<!-- used for the blinking cursor effect -->

plugin:

(function ($) {
  // writes the string
  //
  // @param jQuery $target
  // @param String str
  // @param Numeric cursor
  // @param Numeric delay
  // @param Function cb
  // @return void
  function typeString($target, str, cursor, delay, cb) {
    $target.html(function (_, html) {
      return html + str[cursor];
    });
    
    if (cursor < str.length - 1) {
      setTimeout(function () {
        typeString($target, str, cursor + 1, delay, cb);
      }, delay);
    }
    else {
      cb();
    }
  }
  
  // clears the string
  //
  // @param jQuery $target
  // @param Numeric delay
  // @param Function cb
  // @return void
  function deleteString($target, delay, cb) {
    var length;
    
    $target.html(function (_, html) {
      length = html.length;
      return html.substr(0, length - 1);
    });
    
    if (length > 1) {
      setTimeout(function () {
        deleteString($target, delay, cb);
      }, delay);
    }
    else {
      cb();
    }
  }

  // jQuery hook
  $.fn.extend({
    teletype: function (opts) {
      var settings = $.extend({}, $.teletype.defaults, opts);
      
      return $(this).each(function () {
        (function loop($tar, idx) {
          // type
          typeString($tar, settings.text[idx], 0, settings.delay, function () {
            // delete
            setTimeout(function () {
              deleteString($tar, settings.delay, function () {
                loop($tar, (idx + 1) % settings.text.length);
              });
            }, settings.pause);
          });
        
        }($(this), 0));
      });
    }
  });

  // plugin defaults  
  $.extend({
    teletype: {
      defaults: {
        delay: 100,
        pause: 5000,
        text: []
      }
    }
  });
}(jQuery));

html:

<span id="target"></span>
<span id="cursor"></span> <!-- used for the blinking cursor effect -->

init:

$('#target').teletype({
  text: [
    'Lorem ipsum dolor sit amet, consetetur sadipscing elitr,',
    'sed diam nonumy eirmod tempor invidunt ut labore et dolore',
    'magna aliquyam erat, sed diam voluptua. At vero eos et',
    'accusam et justo duo dolores et ea rebum. Stet clita kasd',
    'gubergren, no sea takimata sanctus est Lorem ipsum dolor sit',
    'amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr,',
    'sed diam nonumy eirmod tempor invidunt ut labore et dolore',
    'magna aliquyam erat, sed diam voluptua. At vero eos et accusam',
    'et justo duo dolores et ea rebum. Stet clita kasd gubergren,',
    'no sea takimata sanctus est Lorem ipsum dolor sit amet.'
  ]
});

$('#cursor').teletype({
  text: ['_', ' '],
  delay: 0,
  pause: 500
});