<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>javascript</title>
<style type="text/css">
body {
font-size: 12px;
}
#txt {
height: 400px;
width: 600px;
border: #333 solid 1px;
padding: 5px;
}
p {
line-height: 18px;
text-indent: 2em;
}
</style>
</head>
<body>
<h2 id="con">JavaScript课程</h2>
<div id="txt">
<h5>JavaScript为网页添加动态效果并实现与用户交互的功能。</h5>
<p>1. JavaScript入门篇，让不懂JS的你，快速了解JS。</p>
<p>2. JavaScript进阶篇，让你掌握JS的基础语法、函数、数组、事件、内置对象、BOM浏览器、DOM操作。</p>
<p>3. 学完以上两门基础课后，在深入学习JavaScript的变量作用域、事件、对象、运动、cookie、正则表达式、ajax等课程。</p>
</div>
<form>
<input type="button" value="改变颜色" onclick="changeColor()">
<input type="button" value="改变宽高" onclick="changeWidth()">
<input type="button" value="隐藏内容" onclick="changeHide()">
<input type="button" value="显示内容" onclick="changeShow()">
<input type="button" value="取消设置" onclick="changeCancel()">
<input type="button" value="点击提示" onclick="numAlert()">
</form>
<script type="text/javascript">
function numAlert() {
alert("哈哈哈")
}
var num = document.getElementById("txt");
function changeColor() {
num.style.color = "red";
num.style.backgroundColor = "blue";
}
function changeWidth() {
num.style.width = "700px";
num.style.height = "900px";
}
function changeHide() {
num.style.display = "none";
}
function changeShow() {
num.style.display = "block";
}
function changeCancel() {
var numFive = confirm("是否要取消以上设置?");
if (numFive == true) {
num = "txt";
} else();
}
</script>
</body>
</html>
找到问题了,是最后的else()写的小括号,改成大括号就行了
onClick