1) Design a function, print message and assign the function to a variable and print it like a function
1)设计一个功能，打印消息并将该功能分配给变量，然后像打印功能一样打印
<html lang="en">
<head>
<script>
function hello(){
document.write("Hello <Br />")
}
hello();
a=hello;
a();
</script>
</head>
<body>
</body>
</html>
Output
输出量
Hello
Hello
2) Call a function and then define it
2)调用一个函数，然后定义它
<html lang="en">
<head>
<script>
hello();
function hello(){
document.write("Hello <Br />")
}
</script>
</head>
<body>
</body>
</html>
Output
输出量
Hello
3) Define a function and call it in the body section
3)定义一个函数并在主体部分中调用它
<html lang="en">
<head>
<script>
function hello(){
document.write("Hello <Br />")
}
</script>
</head>
<body>
<script>
hello();
</script>
</body>
</html>
Output
输出量
Hello
4) Call a function in head section and define it in the body section
4)在头部分调用一个函数，然后在主体部分定义它
<html lang="en">
<head>
<script>
hello();
</script>
</head>
<body>
<script>
function hello(){
document.write("Hello <Br />")
}
</script>
</body>
</html>
Output
输出量
None: Function will not call
5) Call a function and define it in the body section
5)调用函数并在主体部分中定义
<html lang="en">
<head>
<script>
</script>
</head>
<body>
<script>
hello();
function hello(){
document.write("Hello <Br />")
}
</script>
</body>
</html>
Output
输出量
Hello
翻译自: https://www.includehelp.com/code-snippets/examples-of-user-defined-functions.aspx
