简化 jQuery 以检测输入值的变化 [重复]

Question

我正在跟踪输入到 textarea 中的字符数

$(function(){
  var limitDiv = $("#limit");
  var limit = limitDiv.data("limit");
  var button = $("input");
  $("textarea").on("keyup", function(){
    var total = this.value.length;
    var diff = limit- total;
    var condition = diff < 0 || total === 0;
    limitDiv.text(diff).toggleClass("red", condition);
    button.prop("disabled", condition);
  }).trigger("keyup");
})

Answer 1

只需添加一个粘贴事件：

$(function(){
  var limitDiv = $("#limit");
  var limit = limitDiv.data("limit");
  var button = $("input");
  $("textarea").on("keyup paste", function(){
    var total = this.value.length;
    var diff = limit- total;
    var condition = diff < 0 || total === 0;
    limitDiv.text(diff).toggleClass("red", condition);
    button.prop("disabled", condition);
    button.value(total);
  });
})

textarea {
  width: 100%;
  height: 30px;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<textarea></textarea>
<input type="button" value="Submit">
<div id="limit" data-limit="15"></div>

Answer 2

在 jQuery 中有一个paste 事件，虽然它不经常使用。截至jQuery 2.1.0.

，它似乎仍然有效

$("#input").on("paste", function(e){
      //code goes here
  }); 

http://jsfiddle.net/gty70qc9/2/