关于函数的调用疑问
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
<style type="text/css">
#div1{width:200px;height:30px;background-color:red;}
#div2{width:150px; height:20px;background-color:gray;margin-top:10px;display:none;}
</style>
<script type="text/javascript">
window.onload = function () {
var div1 = document.getElementById("div1");
var div2 = document.getElementById("div2");
var timer = null;
function show() {
div2.style.display = "block";
clearTimeout(timer);
}
function hide() {
timer = setTimeout(function () { div2.style.display = "none"; }, 300);
}
div1.onmouseover = show;
div1.onmouseout = hide;
div2.onmouseover = show;
div2.onmouseout = hide;
}
</script>
</head>
<body>
<div id="div1"></div>
<div id="div2"></div>
</body>
</html>div1.onmouseover = show; div1.onmouseout = hide; div2.onmouseover = show; div2.onmouseout = hide;为啥我要是写成div1.onmouseover = show(); div1.onmouseout = hide(); div2.onmouseover = show(); div2.onmouseout = hide();就不行呢？函数的调用不得加上后面的括号吗？求解答
天窗的蚂蚁浏览 1320回答 1
1回答
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慕无忌8876879
加上括号，你的方法就执行了，但是不会赋值给你的div1.onmouseover了，当出发你的div1.onmouseover的时候就不会调用show了
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JavaScript