Javascript What is a function?
A function is a set of statements that perform a specific function. Without functions, it might take five, ten, or more lines of code to complete the task. At this time, we can put the code block that performs a specific function into a function and call this function directly, saving the trouble of repeatedly entering a large amount of code.
How to define a function
function function name(){
Function code segment;
}
Note:
#1. function is the keyword that defines the function.
2. "Function name" is the name you give the function.
3. Replace "function code" with a code that completes a specific function
Let's write an example below, the following code:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>函数</title>
<script type="text/javascript">
function sum(){
var a=10;
var b=5;
var c= a+b;
document.write(c);
}
</script>
</head>
<body>
</body>
</html>As with the above code, we write functions one by one , the function of the function is to find the sum of a+b. Now how do we use the function?
How to call the function
Syntax: function name();
So in the example we wrote above, how should we output the function, as follows:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>函数</title>
<script type="text/javascript">
function sum(){
var a=10;
var b=5;
var c= a+b;
document.write(c);
}
sum();
</script>
</head>
<body>
</body>
</html>In this way we can call the function, and the output result is 15;
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