如何以编程方式更改选择以激活其onchange行为？
问题描述：
这似乎不起作用：
<select id="mySel" onchange="alert('foo')">
<option value="a">a</option>
<option value="b">b</option>
</select>
<script>
dojo.byId('mySel').value = 'b'; // select changes, but nothing is alerted
</script>
（我正在使用dojo，但这并不重要。）
(I'm using dojo, but that doesn't really matter.)
答
onchange名称有点误导，除非您了解更改事件并且更改的值不是'同样的事情。当用户更改浏览器中的值时，会发生更改事件。我相信您可以通过在以编程方式更改值之后调用 dojo.byId（'mySel'）。onchange（）来手动触发事件。 （你可能需要实际定义一个调用 alert 的函数。我自己没有这样做。）
The 'onchange' name is a little misleading unless you understand that a change event and a value being changed aren't the same thing. A change event occurs when the user changes the value in the browser. I believe you can fire the event manually by calling dojo.byId('mySel').onchange() after you programmatically change the value, though. (You might need to actually define a function that calls alert, though. I haven't done this myself.)