To summarize, here are some commonly used ways to introduce js code:
1. Introduction of the page header (within the head tag);
2. Introduced into the page (within the body tag);
3. Introduce external JS files;
1. Introducing JS into the header of the page
<!DOCTYPE html>
<html>
<head>
<title></title>
<script type="text/javascript">
//这里编写JavaScript程序
</script>
</head>
<body>
</body>
</html>2. Introduce JS into the page
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<script type="text/javascript">
//这里编写JavaScript程序
</script>
</body>
</html>3. Introduce external JS files
<script src="js/index.js" type="text/javascript"></script>