js代码

<script type="text/javascript">
		(function($) {
		  function getRandomInt(min, max) {
		    return Math.floor(Math.random() * (max - min + 1)) + min;
		  }
		  $.fn.animChars = function(options) {
		    var params = $.extend(
		      {
		        duration: 1,
		        upperLimit: 150,
		        sizeInterval: [15, 80]
		      },
		      options
		    );
		    $(this).keypress(function(e) {
		      console.log(this.selectionStart)
		      var rand = getRandomInt(1, 9);
		      var randP = Math.floor(Math.random() * 10);
		      randP < 5 ? (randP = rand) : (randP = rand - rand * 2);

		      var c = String.fromCharCode(e.which);
		      $(this).parent().append("<span class='cl" + rand + "'>" + c + "</span>");

		      $(this)
		        .parent()
		        .find("span.cl" + rand + "")
		        .css({
		          left: getRandomInt(0, 90) + "%",
		          "font-size": getRandomInt(
		            params.sizeInterval[0],
		            params.sizeInterval[1]
		          )
		        })
		        .fadeIn(100, function() {
		          $(this)
		            .css({
		              "margin-bottom": getRandomInt(
		                params.upperLimit - params.upperLimit / 2
		                  ? params.upperLimit / 2
		                  : 0,
		                params.upperLimit
		              ),
		              "margin-left": randP * 10
		            })
		            .fadeOut(params.duration * 1000, function() {
		              $(this).remove();
		            });
		        });
		    });
		  };
		})(jQuery);

		$(document).ready(function() {
		  $("input").animChars({
		    duration: 0.8,
		    upperLimit: 200,
		    sizeInterval: [15, 80]
		  });
		});
	</script>