jQuery的變化事件不觸發

Question

該事件由於某種原因未觸發

<div id="plotSelectionBar">
    <span>Select What to plot</span>
    <select class="plotSelector" id="firstDropdown">
        <option value="A">A</option>
        <option value="B">B</option>
        <option value="C">C</option>                
    </select>

    <span>Select What to plot2</span>
    <select class="plotSelector" id="secondDropdown">
        <option value="A">A</option>
        <option value="B">B</option>
        <option value="C">C</option>                
    </select>
 </div>

事件句柄如下：

$('.plotSelector').change(function(e)
{ if (this.id="firstDropdown)
  {
  //do something
  }
  else {//do something}
});

在此事件之上，我還有另一個事件句柄可以觸發。 這是怎么回事？

Answer 1

您有語法錯誤，僅在使用元素更改事件之后需要調用文檔准備就緒

 $( document ).ready(function() { $('.plotSelector').change(function(e){ if(this.id == "firstDropdown") alert(1) else { alert(2) } }) }); 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script> <div id="plotSelectionBar"> <span>Select What to plot</span> <select class="plotSelector" id="firstDropdown"> <option value="A">A</option> <option value="B">B</option> <option value="C">C</option> </select> <span>Select What to plot2</span> <select class="plotSelector" id="secondDropdown"> <option value="A">A</option> <option value="B">B</option> <option value="C">C</option> </select> </div>