一、javascrit放在哪些文件中
1、放在<script>标签中
（1）直接放
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
</head>
<body>
<script type="text/javascript">
document.write("初学javascript")
document.write("<h1>hello javascript</h1>")
</script>
</body>
</html>
代码运行结果是
（2）再把<script>标签放在<div>标签中
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
</head>
<body>
<div>
<script type="text/javascript">
document.write("初学javascript")
document.write("<h1>hello javascript</h1>")
</script>
</div>
</body>
</html>
代码运行结果是一样
![image_thumb[1]](https://img2018.cnblogs.com/blog/1813612/201910/1813612-20191004145552470-1411271386.png "image_thumb[1]")
![image_thumb[1]](https://img2018.cnblogs.com/blog/1813612/201910/1813612-20191004145552022-2145074049.png "image_thumb[1]")
2、放外部文件中
![image_thumb[1][1]](https://img2018.cnblogs.com/blog/1813612/201910/1813612-20191004145553411-1116595821.png "image_thumb[1][1]")
![image_thumb[1][1]](https://img2018.cnblogs.com/blog/1813612/201910/1813612-20191004145552942-1339547725.png "image_thumb[1][1]")
export.js文件的代码：
/**
* Created by pere on 2019-10-04.
*/
document.write("初学javascript")
document.write("<h1>hello javascript</h1>")
test1中的代码：
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
<script type="text/javascript" src="export.js"></script>
</head>
<body>
</body>
</html>
运行结果是
![image_thumb[2]](https://img2018.cnblogs.com/blog/1813612/201910/1813612-20191004145554378-1171753513.png "image_thumb[2]")
![image_thumb[2]](https://img2018.cnblogs.com/blog/1813612/201910/1813612-20191004145553879-1434677205.png "image_thumb[2]")
3、放在HTML标签中
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
</head>
<body>
<input type="button" value="弹出消息" onclick="javascript:alert('欢迎你')">
</body>
</html>
代码运行结果：onlcick事件
![image_thumb[4]](https://img2018.cnblogs.com/blog/1813612/201910/1813612-20191004145555330-664402565.png "image_thumb[4]")
![image_thumb[4]](https://img2018.cnblogs.com/blog/1813612/201910/1813612-20191004145554883-1889717429.png "image_thumb[4]"){kind=small}
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
<!--<script type="text/javascript" src="export.js"></script>-->
</head>
<body>
<a onclick="javascript:alert('欢迎你')" href="javascript:alert('a标签弹出')">a标签</a>
</body>
</html>
运行代码的结果
![image_thumb[5]](https://img2018.cnblogs.com/blog/1813612/201910/1813612-20191004145556271-446165264.png "image_thumb[5]")
点击a标签后弹出![image_thumb[5]](https://img2018.cnblogs.com/blog/1813612/201910/1813612-20191004145555780-287459964.png "image_thumb[5]")
![image_thumb[7]](https://img2018.cnblogs.com/blog/1813612/201910/1813612-20191004145557250-646070896.png "image_thumb[7]")
![image_thumb[7]](https://img2018.cnblogs.com/blog/1813612/201910/1813612-20191004145556781-448118915.png "image_thumb[7]")
点击确定后弹出
![image_thumb[9]](https://img2018.cnblogs.com/blog/1813612/201910/1813612-20191004145558178-105633913.png "image_thumb[9]")
![image_thumb[9]](https://img2018.cnblogs.com/blog/1813612/201910/1813612-20191004145557717-693955361.png "image_thumb[9]")
二、javascript的小综合应用感知
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
<!--<script type="text/javascript" src="export.js"></script>-->
</head>
<body>
<!--<input type="button" value="弹出消息" onclick="alert('欢迎你')">-->
<!--<a onclick="javascript:alert('欢迎你')" href="javascript:alert('a标签弹出')">a标签</a>-->
<input type="button" value="函数测试" onclick="fordemo(3)">
<script type="text/javascript">
function fordemo(count){
var i=0;
for(i=0;i<=count;i++){
document.write("这是第"+i+"个数字，他的值为"+(i+1)+"<br/>")
}
}
</script>
</body>
</html>
代码运行结果是：代码里面有输出为HTML标签的内容会被解释为标签输出
点击后出现
![image_thumb[11]](https://img2018.cnblogs.com/blog/1813612/201910/1813612-20191004145558628-1627950515.png "image_thumb[11]")
![image_thumb[13]](https://img2018.cnblogs.com/blog/1813612/201910/1813612-20191004145559650-2136876561.png "image_thumb[13]")
三、javascript知识点框架
1、ECMAScript：javascript的基础语法等
2、BOM：浏览器的相关操作
（1）javascript的BOM有哪些？如window、location、javascript事件等
（2）javascript弹窗，window:alert()等
（3）location对象，location.assign()等
（4）javascript事件，setTimeout()等
3、DOM:HTML文档的相关操作
（1）查找HTML元素，document.getElementById()
（2）改变HTML内容，document.write()
（3）改变css，document.getElementById(“p”).style.background=”red”