1) Design a function, print message and assign the function to a variable and print it like a function
1)設計一個功能，打印消息并將該功能分配給變量，然后像打印功能一樣打印
<html lang="en">
<head>
<script>
function hello(){
document.write("Hello <Br />")
}
hello();
a=hello;
a();
</script>
</head>
<body>
</body>
</html>
Output
輸出量
Hello
Hello
2) Call a function and then define it
2)調用一個函數，然后定義它
<html lang="en">
<head>
<script>
hello();
function hello(){
document.write("Hello <Br />")
}
</script>
</head>
<body>
</body>
</html>
Output
輸出量
Hello
3) Define a function and call it in the body section
3)定義一個函數并在主體部分中調用它
<html lang="en">
<head>
<script>
function hello(){
document.write("Hello <Br />")
}
</script>
</head>
<body>
<script>
hello();
</script>
</body>
</html>
Output
輸出量
Hello
4) Call a function in head section and define it in the body section
4)在頭部分調用一個函數，然后在主體部分定義它
<html lang="en">
<head>
<script>
hello();
</script>
</head>
<body>
<script>
function hello(){
document.write("Hello <Br />")
}
</script>
</body>
</html>
Output
輸出量
None: Function will not call
5) Call a function and define it in the body section
5)調用函數并在主體部分中定義
<html lang="en">
<head>
<script>
</script>
</head>
<body>
<script>
hello();
function hello(){
document.write("Hello <Br />")
}
</script>
</body>
</html>
Output
輸出量
Hello
翻譯自: https://www.includehelp.com/code-snippets/examples-of-user-defined-functions.aspx
