Question

    <!doctype html>
<html>  
<head>  
<title></title>
<!--binding handlers to object-->
<script type="text/javascript">
<!--
function showAuthor()
{
alert("oscar wilde");  
}
function enableEvent()
{
document.getElementById('someText').attachEvent("onmouseover",showAuthor);              
}               
function disableEvent()
{
someText.detachEvent("onmouseover",showAuthor);
}
//-->
</script>
</head>
<body onload="enableEvent();">
<em id="someText">we may be in the gutter ,but some of us are looking at the stars</em>
<form action="#" method="get">
<input type="button" value="Attach event" onclick="enableEvent();" /> 
<input type="button" value="Detach event" onclick="disableEvent();" />
<input type="button" value="show author" onclick="showAuthor();" />
</form>
</body>
</html>

我已经使用上面的代码来实现事件处理程序，但是当我执行程序时，事件处理程序没有附加。为什么呢？

Answer 1

此

document.getElementById('someText').attachEvent("onmouseover",showAuthor);

应该是这样的

document.getElementById('someText').addEventListener("mouseover",showAuthor, false);

您不想附加活动，但想要添加事件监听器。

此外，您不想分离任何事件，但是您想要删除一个事件侦听器，其语法如下：

document.getElementById("someText").removeEventListener("mouseover",showAuthor, false);

var someText = document.getElementById("someText");

function showAuthor(){
    alert("oscar wilde");  
}

function enableEvent(){
    someText.addEventListener("mouseover",showAuthor, false);         
}            

function disableEvent(){
    someText.removeEventListener("mouseover",showAuthor, false);
}

<body onload="enableEvent()">
<em id="someText">we may be in the gutter ,but some of us are looking at the stars</em>
<form action="#" method="get">
<input type="button" value="Attach event" onclick="enableEvent()" /> 
<input type="button" value="Detach event" onclick="disableEvent();" />
<input type="button" value="show author" onclick="showAuthor()" />
</form>
</body>

有关上述内容的详细说明，请查看以下链接：

Answer 2

我猜你需要使用addEventListener。使用addEventListener时，您无需在＆＃34;上使用＆＃34;带有事件名称的前缀。

<强> 段：

＆＃13;

<script type="text/javascript">
  function showAuthor() {
    alert("oscar wilde");
  }

  function enableEvent() {
    document.getElementById('someText').addEventListener('mouseover', showAuthor);
  }

  function disableEvent() {
    document.getElementById('someText').removeEventListener('mouseover', showAuthor);
  }
</script>

<body onload="enableEvent();">
  <em id="someText">we may be in the gutter ,but some of us are looking at the stars</em>
  <form action="#" method="get">
    <input type="button" value="Attach event" onclick="enableEvent();" />
    <input type="button" value="Detach event" onclick="disableEvent();" />
    <input type="button" value="show author" onclick="showAuthor();" />
  </form>

＆＃13;

希望这有帮助。

事件没有被添加

2 个答案: